Mc. Thaller et al., CONSERVED SEQUENCE MOTIFS AMONG BACTERIAL, EUKARYOTIC, AND ARCHAEAL PHOSPHATASES THAT DEFINE A NEW PHOSPHOHYDROLASE SUPERFAMILY, Protein science, 7(7), 1998, pp. 1647-1652
Members of a new molecular family of bacterial nonspecific acid phosph
atases (NSAPs), indicated as class C, were found to share significant
sequence similarities to bacterial class B NSAPs and to some plant aci
d phosphatases, representing the first example of a family of bacteria
l NSAPs that has a relatively close eukaryotic counterpart. Despite th
e lack of an overall similarity, conserved sequence motifs were also i
dentified among the above enzyme families (class B and class C bacteri
al NSAPs, and related plant phosphatases) and several other families o
f phosphohydrolases, including bacterial phosphoglycolate phosphatases
, histidinol-phosphatase domains of the bacterial bifunctional enzymes
imidazole-glycerolphosphate dehydratases, and bacterial, eukaryotic,
and archaeal phosphoserine phosphatases and threalose-6-phosphatases.
These conserved motifs are clustered within two domains, separated by
a variable spacer region, according to the pattern [FILMAVT]-D-[ILFRMV
Y]-D-[GSNDE]-[TV]-[ILVAM]- [ATSVILMC]-X-{YFWHKR}-X-{YFWHNQ}-X(102, 191
)- {KRHNQ}-G-D-{FYWHILVMC}-{QNH}-{FWYGP}-D- {PSNQYW}. The dephosphoryl
ating activity common to all these proteins supports the definition of
this phosphatase motif and the inclusion of these enzymes into a supe
rfamily of phosphohydrolases that we propose to indicate as ''DDDD'' a
fter the presence of the four invariant aspartate residues. Database s
earches retrieved various hypothetical proteins of unknown function co
ntaining this or similar motifs, far which a phosphohydrolase activity
could be hypothesized.