test_prodoc
PDOC00100
prosite_refs
    ('PS00107', 'PROTEIN_KINASE_ATP')
    ('PS00108', 'PROTEIN_KINASE_ST')
    ('PS00109', 'PROTEIN_KINASE_TYR')
    ('PS50011', 'PROTEIN_KINASE_DOM')
******************************************
* Protein kinases signatures and profile *
******************************************

Eukaryotic  protein kinases [1 to 5]  are  enzymes  that   belong  to  a  very
extensive family of  proteins which share a conserved catalytic core common to
both serine/threonine and  tyrosine protein kinases.  There  are  a  number of
conserved regions in the catalytic domain of protein kinases. We have selected
two of these regions to build signature patterns.  The  first region, which is
located in the N-terminal extremity of the catalytic domain, is a glycine-rich
stretch of residues in the vicinity  of a lysine residue, which has been shown
to be involved in ATP binding.   The second  region,  which is  located in the
central part of the  catalytic  domain,  contains  a  conserved  aspartic acid
residue  which is important for the catalytic activity  of  the enzyme [6]; we
have derived  two signature patterns for that region: one specific for serine/
threonine kinases  and  the  other  for  tyrosine kinases. We also developed a
profile which is based on the alignment in [1] and covers the entire catalytic
domain.

-Consensus pattern: [LIV]-G-{P}-G-{P}-[FYWMGSTNH]-[SGA]-{PW}-[LIVCAT]-{PD}-x-
                    [GSTACLIVMFY]-x(5,18)-[LIVMFYWCSTAR]-[AIVP]-[LIVMFAGCKR]-K
                    [K binds ATP]
-Sequences known to belong to this class detected by the pattern: the majority
 of known  protein  kinases  but it fails to find a number of them, especially
 viral kinases  which  are  quite  divergent in this region and are completely
 missed bythis pattern.
-Other sequence(s) detected in SWISS-PROT: 35.

-Consensus pattern: [LIVMFYC]-x-[HY]-x-D-[LIVMFY]-K-x(2)-N-[LIVMFYCT](3)
                    [D is an active site residue]
-Sequences known to belong to this class detected by the pattern: Most serine/
 threonine  specific protein  kinases  with  10 exceptions (half of them viral
 kinases) and  also  Epstein-Barr  virus BGLF4 and Drosophila ninaC which have
 respectively Ser and Arg instead of the conserved Lys and which are therefore
 detected by the tyrosine kinase specific pattern described below.
-Other sequence(s) detected in SWISS-PROT: 1.

-Consensus pattern: [LIVMFYC]-x-[HY]-x-D-[LIVMFY]-[RSTAC]-x(2)-N-[LIVMFYC](3)
                    [D is an active site residue]
-Sequences known to belong to this class detected by the pattern: ALL tyrosine
 specific protein  kinases  with  the  exception of human ERBB3 and mouse blk.
 This pattern    will    also    detect    most    bacterial    aminoglycoside
 phosphotransferases [8,9]  and  herpesviruses ganciclovir kinases [10]; which
 are proteins structurally and evolutionary related to protein kinases.
-Other sequence(s) detected in SWISS-PROT: 15.

-Sequences known to belong to this class detected by the profile: ALL,  except
 for three  viral  kinases.  This  profile  also  detects  receptor  guanylate
 cyclases (see   <PDOC00430>)  and  2-5A-dependent  ribonucleases.    Sequence
 similarities between  these  two  families  and the eukaryotic protein kinase
 family have been noticed before. It also detects Arabidopsis thaliana kinase-
 like protein TMKL1 which seems to have lost its catalytic activity.
-Other sequence(s) detected in SWISS-PROT: 4.

-Note: if a protein  analyzed  includes the two protein kinase signatures, the
 probability of it being a protein kinase is close to 100%
-Note: eukaryotic-type protein  kinases  have  also  been found in prokaryotes
 such as Myxococcus xanthus [11] and Yersinia pseudotuberculosis.
-Note: the  patterns  shown  above has been updated since their publication in
 [7].
-Note: this  documentation  entry  is linked  to both signature patterns and a
 profile. As  the profile is much more sensitive than the patterns, you should
 use it if you have access to the necessary software tools to do so.

-Expert(s) to contact by email:
                   Hunter T.; hunter@salk-sc2.sdsc.edu
                   Quinn A.M.; quinn@biomed.med.yale.edu

-Last update: November 1995 / Patterns and text revised; profile added.


references
1
Hanks S.K., Hunter T.
FASEB J. 9:576-596(1995).
2
Hunter T.
Meth. Enzymol. 200:3-37(1991).
3
Hanks S.K., Quinn A.M.
Meth. Enzymol. 200:38-62(1991).
4
Hanks S.K.
Curr. Opin. Struct. Biol. 1:369-383(1991).
5
Hanks S.K., Quinn A.M., Hunter T.
Science 241:42-52(1988).
6
Knighton D.R., Zheng J., Ten Eyck L.F., Ashford V.A., Xuong N.-H.,
Taylor S.S., Sowadski J.M.
Science 253:407-414(1991).
7
Bairoch A., Claverie J.-M.
Nature 331:22(1988).
8
Benner S.
Nature 329:21-21(1987).
9
Kirby R.
J. Mol. Evol. 30:489-492(1992).
10
Littler E., Stuart A.D., Chee M.S.
Nature 358:160-162(1992).
11
Munoz-Dorado J., Inouye S., Inouye M.
Cell 67:995-1006(1991).
PDOC00113
prosite_refs
    ('PS00123', 'ALKALINE_PHOSPHATASE')
************************************
* Alkaline phosphatase active site *
************************************

Alkaline phosphatase (EC 3.1.3.1) (ALP) [1] is a zinc and magnesium-containing
metalloenzyme  which hydrolyzes phosphate esters, optimally at high pH.  It is
found in nearly  all living organisms,  with the exception of some plants.  In
Escherichia coli, ALP (gene phoA) is found in the periplasmic space.  In yeast
it (gene  PHO8)  is  found  in  lysosome-like vacuoles and in mammals, it is a
glycoprotein attached to the membrane by a GPI-anchor.

In mammals, four different isozymes are currently known [2]. Three of them are
tissue-specific:  the  placental,  placental-like (germ cell)   and intestinal
isozymes.  The fourth form is  tissue non-specific and was previously known as
the liver/bone/kidney isozyme.

Streptomyces' species  involved  in  the  synthesis  of  streptomycin (SM), an
antibiotic, express  a  phosphatase (EC 3.1.3.39) (gene strK) which is  highly
related to ALP.   It specifically cleaves  both  streptomycin-6-phosphate and,
more slowly, streptomycin-3"-phosphate.

A serine is involved   in the catalytic activity of ALP. The region around the
active site serine is relatively well conserved and can be used as a signature
pattern.

-Consensus pattern: [IV]-x-D-S-[GAS]-[GASC]-[GAST]-[GA]-T
                    [S is the active site residue]
-Sequences known to belong to this class detected by the pattern: ALL.
-Other sequence(s) detected in SWISS-PROT: 3.
-Last update: June 1994 / Text revised.


references
1
Trowsdale J., Martin D., Bicknell D., Campbell I.
Biochem. Soc. Trans. 18:178-180(1990).
2
Manes T., Glade K., Ziomek C.A., Millan J.L.
Genomics 8:541-554(1990).
3
Mansouri K., Piepersberg W.
Mol. Gen. Genet. 228:459-469(1991).
PDOC00144
prosite_refs
    ('PS00159', 'ALDOLASE_KDPG_KHG_1')
    ('PS00160', 'ALDOLASE_KDPG_KHG_2')
*************************************************
* KDPG and KHG aldolases active site signatures *
*************************************************

4-hydroxy-2-oxoglutarate aldolase (EC 4.1.3.16)  (KHG-aldolase)  catalyzes the
interconversion of  4-hydroxy-2-oxoglutarate  into  pyruvate  and  glyoxylate.
Phospho-2-dehydro-3-deoxygluconate  aldolase   (EC 4.1.2.14)   (KDPG-aldolase)
catalyzes the interconversion of  6-phospho-2-dehydro-3-deoxy-D-gluconate into
pyruvate and glyceraldehyde 3-phosphate.

These two enzymes are structurally and functionally related [1]. They are both
homotrimeric proteins of approximately 220 amino-acid residues. They are class
I aldolases whose catalytic mechanism involves  the formation of a Schiff-base
intermediate  between  the  substrate  and the epsilon-amino group of a lysine
residue. In both enzymes, an arginine is required for catalytic activity.

We developed  two signature patterns for these enzymes. The first one contains
the active  site  arginine  and the second, the lysine involved in the Schiff-
base formation.

-Consensus pattern: G-[LIVM]-x(3)-E-[LIV]-T-[LF]-R
                    [R is the active site residue]
-Sequences known to belong to this class detected by the pattern: ALL,  except
 for Bacillus  subtilis  KDPG-aldolase  which  has  Thr  instead of Arg in the
 active site.
-Other sequence(s) detected in SWISS-PROT: NONE.

-Consensus pattern: G-x(3)-[LIVMF]-K-[LF]-F-P-[SA]-x(3)-G
                    [K is involved in Schiff-base formation]
-Sequences known to belong to this class detected by the pattern: ALL.
-Other sequence(s) detected in SWISS-PROT: NONE.

-Last update: November 1997 / Patterns and text revised.


references
1
Vlahos C J., Dekker E.E.
J. Biol. Chem. 263:11683-11691(1988).
PDOC00149
prosite_refs
    ('PS00165', 'DEHYDRATASE_SER_THR')
**********************************************************************
* Serine/threonine dehydratases pyridoxal-phosphate attachment site  *
**********************************************************************

Serine and threonine  dehydratases [1,2]  are  functionally  and  structurally
related pyridoxal-phosphate dependent enzymes:

 - L-serine dehydratase (EC 4.2.1.13) and D-serine  dehydratase  (EC 4.2.1.14)
   catalyze the dehydratation of L-serine (respectively D-serine) into ammonia
   and pyruvate.
 - Threonine dehydratase  (EC 4.2.1.16) (TDH) catalyzes  the  dehydratation of
   threonine into  alpha-ketobutarate  and  ammonia.  In Escherichia coli  and
   other microorganisms,  two  classes  of  TDH  are  known  to  exist. One is
   involved in  the  biosynthesis of isoleucine, the other in hydroxamino acid
   catabolism.

Threonine synthase  (EC 4.2.99.2) is  also  a pyridoxal-phosphate  enzyme,  it
catalyzes the  transformation of  homoserine-phosphate into threonine.  It has
been shown [3] that  threonine  synthase  is  distantly related to the serine/
threonine dehydratases.

In all these enzymes, the pyridoxal-phosphate group is  attached  to a  lysine
residue.  The sequence around  this residue is sufficiently conserved to allow
the derivation  of  a  pattern  specific  to serine/threonine dehydratases and
threonine synthases.

-Consensus pattern: [DESH]-x(4,5)-[STVG]-x-[AS]-[FYI]-K-[DLIFSA]-[RVMF]-[GA]-
                    [LIVMGA]
                    [The K is the pyridoxal-P attachment site]
-Sequences known to belong to this class detected by the pattern: ALL.
-Other sequence(s) detected in SWISS-PROT: 12.

-Note: some   bacterial L-serine dehydratases - such as those from Escherichia
 coli - are iron-sulfur proteins [4] and do not belong to this family.

-Last update: November 1995 / Pattern and text revised.


references
1
Ogawa H., Gomi T., Konishi K., Date T., Naakashima H., Nose K.,
Matsuda Y., Peraino C., Pitot H.C., Fujioka M.
J. Biol. Chem. 264:15818-15823(1989).
2
Datta P., Goss T.J., Omnaas J.R., Patil R.V.
Proc. Natl. Acad. Sci. U.S.A. 84:393-397(1987).
3
Parsot C.
EMBO J. 5:3013-3019(1986).
4
Grabowski R., Hofmeister A.E.M., Buckel W.
Trends Biochem. Sci. 18:297-300(1993).
PDOC00340
prosite_refs
    ('PS00406', 'ACTINS_1')
    ('PS00432', 'ACTINS_2')
    ('PS01132', 'ACTINS_ACT_LIKE')
*********************
* Actins signatures *
*********************

Actins [1 to 4] are highly conserved contractile  proteins that are present in
all eukaryotic cells. In vertebrates there are three groups of actin isoforms:
alpha, beta and gamma.  The alpha actins are found in muscle tissues and are a
major constituent of the contractile apparatus.  The beta and gamma actins co-
exists in most cell  types as  components of the cytoskeleton and as mediators
of internal cell motility.  In plants [5]  there  are  many isoforms which are
probably involved  in  a  variety of  functions such as cytoplasmic streaming,
cell shape determination,  tip growth,  graviperception, cell wall deposition,
etc.

Actin exists either in a monomeric form (G-actin) or in a polymerized form (F-
actin). Each actin monomer  can  bind a molecule of ATP;  when  polymerization
occurs, the ATP is hydrolyzed.

Actin is a protein of from 374 to 379 amino acid  residues.  The  structure of
actin has been highly conserved in the course of evolution.

Recently some  divergent  actin-like  proteins have been identified in several
species. These proteins are:

 - Centractin  (actin-RPV)  from mammals, fungi (yeast ACT5, Neurospora crassa
   ro-4) and  Pneumocystis  carinii  (actin-II).  Centractin  seems  to  be  a
   component of  a  multi-subunit  centrosomal complex involved in microtubule
   based vesicle motility. This subfamily is also known as ARP1.
 - ARP2  subfamily  which  includes  chicken ACTL, yeast ACT2, Drosophila 14D,
   C.elegans actC.
 - ARP3  subfamily  which includes actin 2 from mammals, Drosophila 66B, yeast
   ACT4 and fission yeast act2.
 - ARP4  subfamily  which includes yeast ACT3 and Drosophila 13E.

We developed  three  signature  patterns. The first two are specific to actins
and span  positions  54 to 64 and 357 to 365. The last signature picks up both
actins and  the actin-like proteins and corresponds to positions 106 to 118 in
actins.

-Consensus pattern: [FY]-[LIV]-G-[DE]-E-A-Q-x-[RKQ](2)-G
-Sequences known to belong to this class detected by the pattern: ALL,  except
 for the actin-like proteins and 10 actins.
-Other sequence(s) detected in SWISS-PROT: NONE.

-Consensus pattern: W-[IV]-[STA]-[RK]-x-[DE]-Y-[DNE]-[DE]
-Sequences known to belong to this class detected by the pattern: ALL,  except
 for the actin-like proteins and 9 actins.
-Other sequence(s) detected in SWISS-PROT: NONE.

-Consensus pattern: [LM]-[LIVM]-T-E-[GAPQ]-x-[LIVMFYWHQ]-N-[PSTAQ]-x(2)-N-[KR]
-Sequences known to belong to this class detected by the pattern: ALL,  except
 for 5 actins.
-Other sequence(s) detected in SWISS-PROT: NONE.

-Last update: November 1997 / Text revised.


references
1
Sheterline P., Clayton J., Sparrow J.C.
(In) Actins, 3rd Edition, Academic Press Ltd, London, (1996).
2
Pollard T.D., Cooper J.A.
Annu. Rev. Biochem. 55:987-1036(1986).
3
Pollard T.D.
Curr. Opin. Cell Biol. 1:33-40(1990).
4
Rubenstein P.A.
BioEssays 12:309-315(1990).
5
Meagher R.B., McLean B.G.
Cell Motil. Cytoskeleton 16:164-166(1990).
PDOC00424
prosite_refs
    ('PS00488', 'PAL_HISTIDASE')
**********************************************************
* Phenylalanine and histidine ammonia-lyases active site *
**********************************************************

Phenylalanine ammonia-lyase (EC 4.3.1.5) (PAL) is  a  key  enzyme of plant and
fungi  phenylpropanoid  metabolism  which is involved in the biosynthesis of a
wide  variety  of secondary metabolites such  as  flavanoids,   furanocoumarin
phytoalexins and  cell  wall  components.  These compounds have many important
roles in plants during normal growth and in responses to environmental stress.
PAL catalyzes  the  removal  of  an  ammonia  group from phenylalanine to form
trans-cinnamate.

Histidine ammonia-lyase (EC 4.3.1.3) (histidase)  catalyzes  the first step in
histidine degradation, the removal of  an  ammonia  group  from  histidine  to
produce urocanic acid.

The two types of enzymes are functionally and  structurally related [1].  They
are the only enzymes  which are known to have the modified amino acid dehydro-
alanine (DHA) in their active site. A serine residue has been shown [2,3,4] to
be the  precursor  of  this  essential electrophilic moiety. The region around
this active  site  residue  is  well  conserved and can be used as a signature
pattern.

-Consensus pattern: G-[STG]-[LIVM]-[STG]-[AC]-S-G-[DH]-L-x-P-L-[SA]-x(2)-[SA]
                    [S is the active site residue]
-Sequences known to belong to this class detected by the pattern: ALL.
-Other sequence(s) detected in SWISS-PROT: NONE.
-Last update: November 1995 / Pattern and text revised.


references
1
Taylor R.G., Lambert M.A., Sexsmith E., Sadler S.J., Ray P.N.,
Mahuran D.J., McInnes R.R.
J. Biol. Chem. 265:18192-18199(1990).
2
Langer M., Reck G., Reed J., Retey J.
Biochemistry 33:6462-6467(1994).
3
Schuster B., Retey J.
FEBS Lett. 349:252-254(1994).
4
Taylor R.G., McInnes R.R.
J. Biol. Chem. 269:27473-27477(1994).
PDOC00472
prosite_refs
    ('PS00546', 'CYSTEINE_SWITCH')
*****************************
* Matrixins cysteine switch *
*****************************

Mammalian extracellular matrix metalloproteinases (EC 3.4.24.-), also known as
matrixins [1] (see <PDOC00129>), are zinc-dependent enzymes. They are secreted
by cells  in an inactive form (zymogen) that differs from the mature enzyme by
the presence  of  an  N-terminal propeptide. A highly conserved octapeptide is
found two  residues  downstream  of the C-terminal end of the propeptide. This
region has been shown to be  involved  in  autoinhibition  of matrixins [2,3];
a cysteine  within the octapeptide chelates  the  active  site  zinc ion, thus
inhibiting the  enzyme.  This  region has been called the 'cysteine switch' or
'autoinhibitor region'.

A cysteine switch has been found in the following zinc proteases:

 - MMP-1 (EC 3.4.24.7) (interstitial collagenase).
 - MMP-2 (EC 3.4.24.24) (72 Kd gelatinase).
 - MMP-3 (EC 3.4.24.17) (stromelysin-1).
 - MMP-7 (EC 3.4.24.23) (matrilysin).
 - MMP-8 (EC 3.4.24.34) (neutrophil collagenase).
 - MMP-9 (EC 3.4.24.35) (92 Kd gelatinase).
 - MMP-10 (EC 3.4.24.22) (stromelysin-2).
 - MMP-11 (EC 3.4.24.-) (stromelysin-3).
 - MMP-12 (EC 3.4.24.65) (macrophage metalloelastase).
 - MMP-13 (EC 3.4.24.-) (collagenase 3).
 - MMP-14 (EC 3.4.24.-) (membrane-type matrix metalliproteinase 1).
 - MMP-15 (EC 3.4.24.-) (membrane-type matrix metalliproteinase 2).
 - MMP-16 (EC 3.4.24.-) (membrane-type matrix metalliproteinase 3).
 - Sea urchin hatching enzyme (EC 3.4.24.12) (envelysin) [4].
 - Chlamydomonas reinhardtii gamete lytic enzyme (GLE) [5].

-Consensus pattern: P-R-C-[GN]-x-P-[DR]-[LIVSAPKQ]
                    [C chelates the zinc ion]
-Sequences known to belong to this class detected by the pattern: ALL,  except
 for cat MMP-7 and mouse MMP-11.
-Other sequence(s) detected in SWISS-PROT: NONE.
-Last update: November 1997 / Pattern and text revised.


references
1
Woessner J. Jr.
FASEB J. 5:2145-2154(1991).
2
Sanchez-Lopez R., Nicholson R., Gesnel M.C., Matrisian L.M.,
Breathnach R.
J. Biol. Chem. 263:11892-11899(1988).
3
Park A.J., Matrisian L.M., Kells A.F., Pearson R., Yuan Z., Navre M.
J. Biol. Chem. 266:1584-1590(1991).
4
Lepage T., Gache C.
EMBO J. 9:3003-3012(1990).
5
Kinoshita T., Fukuzawa H., Shimada T., Saito T., Matsuda Y.
Proc. Natl. Acad. Sci. U.S.A. 89:4693-4697(1992).
PDOC00640
prosite_refs
    ('PS00812', 'GLYCOSYL_HYDROL_F8')
******************************************
* Glycosyl hydrolases family 8 signature *
******************************************

The microbial degradation  of cellulose and  xylans requires  several types of
enzymes such as endoglucanases (EC 3.2.1.4),  cellobiohydrolases (EC 3.2.1.91)
(exoglucanases), or xylanases (EC 3.2.1.8) [1,2].  Fungi and bacteria produces
a spectrum of cellulolytic  enzymes (cellulases)  and  xylanases which, on the
basis of sequence similarities,  can be classified into families. One of these
families is known as the cellulase family D [3] or as  the glycosyl hydrolases
family 8  [4,E1].  The  enzymes  which  are  currently known to belong to this
family are listed below.

 - Acetobacter xylinum endonuclease cmcAX.
 - Bacillus strain KSM-330 acidic endonuclease K (Endo-K).
 - Cellulomonas josui endoglucanase 2 (celB).
 - Cellulomonas uda endoglucanase.
 - Clostridium cellulolyticum endoglucanases C (celcCC).
 - Clostridium thermocellum endoglucanases A (celA).
 - Erwinia chrysanthemi minor endoglucanase y (celY).
 - Bacillus circulans beta-glucanase (EC 3.2.1.73).
 - Escherichia coli hypothetical protein yhjM.

The most conserved region in  these enzymes is  a stretch of about 20 residues
that contains  two conserved aspartate. The first asparatate is thought [5] to
act as the nucleophile in the catalytic mechanism. We have used this region as
a signature pattern.

-Consensus pattern: A-[ST]-D-[AG]-D-x(2)-[IM]-A-x-[SA]-[LIVM]-[LIVMG]-x-A-
                    x(3)-[FW]
                    [The first D is an active site residue]
-Sequences known to belong to this class detected by the pattern: ALL.
-Other sequence(s) detected in SWISS-PROT: NONE.

-Expert(s) to contact by email:
                   Henrissat B.; bernie@afmb.cnrs-mrs.fr

-Last update: November 1997 / Text revised.


references
1
Beguin P.
Annu. Rev. Microbiol. 44:219-248(1990).
2
Gilkes N.R., Henrissat B., Kilburn D.G., Miller R.C. Jr., Warren R.A.J.
Microbiol. Rev. 55:303-315(1991).
3
Henrissat B., Claeyssens M., Tomme P., Lemesle L., Mornon J.-P.
Gene 81:83-95(1989).
4
Henrissat B.
Biochem. J. 280:309-316(1991).
5
Alzari P.M., Souchon H., Dominguez R.
Structure 4:265-275(1996).
E1

http://www.expasy.ch/cgi-bin/lists?glycosid.txt
PDOC00787
prosite_refs
    ('PS01027', 'GLYCOSYL_HYDROL_F39')
******************************************************
* Glycosyl hydrolases family 39 putative active site *
******************************************************

It has  been  shown  [1,E1]  that  the  following  glycosyl  hydrolases can be
classified into a single family on the basis of sequence similarities:

 - Mammalian lysosomal alpha-L-iduronidase (EC 3.2.1.76).
 - Caldocellum  saccharolyticum  and  Thermoanaerobacter saccharolyticum beta-
   xylosidase (EC 3.2.1.37) (gene xynB).

The best  conserved  regions  in  these  enzymes is  located in the N-terminal
section. It   contains  a  glutamic  acid  residue  which,  on  the  basis  of
similarities with other  families of glycosyl hydrolases [2], probably acts as
the proton donor in the catalytic mechanism. We use this region as a signature
pattern.

-Consensus pattern: W-x-F-E-x-W-N-E-P-[DN]
                    [The second E is the putative active site residue]
-Sequences known to belong to this class detected by the pattern: ALL.
-Other sequence(s) detected in SWISS-PROT: NONE.

-Expert(s) to contact by email:
                   Henrissat B.; bernie@afmb.cnrs-mrs.fr

-Last update: November 1997 / Text revised.


references
1
Henrissat B., Bairoch A.
Biochem. J. 293:781-788(1993).
2
Henrissat B., Callebaut I., Fabrega S., Lehn P., Mornon J.-P., Davies G.
Proc. Natl. Acad. Sci. U.S.A. 92:7090-7094(1995).
E1

http://www.expasy.ch/cgi-bin/lists?glycosid.txt
PDOC00933
prosite_refs
    ('PS01213', 'GLOBIN_FAM_2')
**********************************************
* Protozoan/cyanobacterial globins signature *
**********************************************

Globins are heme-containing  proteins involved in  binding and/or transporting
oxygen [1]. Almost all globins belong to a large family (see <PDOC00793>), the
only exceptions  are  the  following proteins which form a family of their own
[2,3]:

 - Monomeric  hemoglobins  from the protozoan Paramecium caudatum, Tetrahymena
   pyriformis and Tetrahymena thermophila.
 - Cyanoglobin from the cyanobacteria Nostoc commune.
 - Globins  LI637  and  LI410  from  the chloroplast of the alga Chlamydomonas
   eugametos.
 - Mycobacterium tuberculosis hypothetical protein MtCY48.23.

These proteins  contain a conserved histidine which could be involved in heme-
binding. As a signature pattern, we use a conserved region that ends with this
residue.

-Consensus pattern: F-[LF]-x(5)-G-[PA]-x(4)-G-[KRA]-x-[LIVM]-x(3)-H
-Sequences known to belong to this class detected by the pattern: ALL.
-Other sequence(s) detected in SWISS-PROT: NONE.
-Last update: November 1997 / First entry.


references
1
Concise Encyclopedia Biochemistry, Second Edition, Walter de Gruyter,
Berlin New-York (1988).
2
Takagi T.
Curr. Opin. Struct. Biol. 3:413-418(1993).
3
Couture M., Chamberland H., St-Pierre B., Lafontaine J., Guertin M.;
Mol. Gen. Genet. 243:185-197(1994).
