 |
PDBsum entry 3be7
|
|
|
|
References listed in PDB file
|
 |
|
Key reference
|
|
|
Title
|
|
Functional identification of incorrectly annotated prolidases from the amidohydrolase superfamily of enzymes.
|
|
|
Authors
|
|
D.F.Xiang,
Y.Patskovsky,
C.Xu,
A.J.Meyer,
J.M.Sauder,
S.K.Burley,
S.C.Almo,
F.M.Raushel.
|
|
|
Ref.
|
|
Biochemistry, 2009,
48,
3730-3742.
|
|
|
PubMed id
|
|
|
|
|
|
|
|
|
Abstract
|
|
|
The substrate profiles for two proteins from Caulobacter crescentus CB15 (Cc2672
and Cc3125) and one protein (Sgx9359b) derived from a DNA sequence ( gi|44368820
) isolated from the Sargasso Sea were determined using combinatorial libraries
of dipeptides and N-acyl derivatives of amino acids. These proteins are members
of the amidohydrolase superfamily and are currently misannotated in NCBI as
catalyzing the hydrolysis of l-Xaa-l-Pro dipeptides. Cc2672 was shown to
catalyze the hydrolysis of l-Xaa-l-Arg/Lys dipeptides and the N-acetyl and
N-formyl derivatives of lysine and arginine. This enzyme will also hydrolyze
longer peptides that terminate in either lysine or arginine. The N-methyl
phosphonate derivative of l-lysine was a potent competitive inhibitor of Cc2672
with a K(i) value of 120 nM. Cc3125 was shown to catalyze the hydrolysis of
l-Xaa-l-Arg/Lys dipeptides but will not hydrolyze tripeptides or the N-formyl
and N-acetyl derivatives of lysine or arginine. The substrate profile for
Sgx9359b is similar to that of Cc2672 except that compounds with a C-terminal
lysine are not recognized as substrates. The X-ray structure of Sgx9359b was
determined to a resolution of 2.3 A. The protein folds as a
(beta/alpha)(8)-barrel and self-associates to form a homooctamer. The active
site is composed of a binuclear metal center similar to that found in
phosphotriesterase and dihydroorotase. In one crystal form, arginine was bound
adventitiously to the eight active sites within the octamer. The orientation of
the arginine in the active site identified the structural determinants for
recognition of the alpha-carboxylate and the positively charged side chains of
arginine-containing substrates. This information was used to identify 18 other
bacterial sequences that possess identical or similar substrate profiles.
|
|
|
|
|
|
|
