PROSITE: PDOC00149 (documentation file)

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# PROSITE: PDOC00149 (documentation)

    {PDOC00149}
    {PS00165; DEHYDRATASE_SER_THR}
    {BEGIN}
    **********************************************************************
    * 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.

    [ 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).

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    {END}

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