 |
PDBsum entry 1m7v
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Oxidoreductase
|
PDB id
|
|
|
|
1m7v
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
 |
Contents |
 |
|
|
|
|
|
|
|
|
|
|
|
|
* Residue conservation analysis
|
|
|
|
|
References listed in PDB file
|
|
|
Key reference
|
|
|
Title
|
|
Structure of a nitric oxide synthase heme protein from bacillus subtilis.
|
|
|
Authors
|
|
K.Pant,
A.M.Bilwes,
S.Adak,
D.J.Stuehr,
B.R.Crane.
|
|
|
Ref.
|
|
Biochemistry, 2002,
41,
11071-11079.
[DOI no: ]
|
|
|
PubMed id
|
|
|
|
|
|
Abstract
|
|
|
Eukaryotic nitric oxide synthases (NOSs) produce nitric oxide to mediate
intercellular signaling and protect against pathogens. Recently, proteins
homologous to mammalian NOS oxygenase domains have been found in prokaryotes and
one from Bacillus subtilis (bsNOS) has been demonstrated to produce nitric oxide
[Adak, S., Aulak, K. S., and Stuehr, D. J. (2002) J. Biol. Chem. 277,
16167-16171]. We present structures of bsNOS complexed with the active cofactor
tetrahydrofolate and the substrate L-arginine (L-Arg) or the intermediate
N(omega)-hydroxy-L-arginine (NHA) to 1.9 or 2.2 A resolution, respectively. The
bsNOS structure is similar to those of the mammalian NOS oxygenase domains
(mNOS(ox)) except for the absence of an N-terminal beta-hairpin hook and
zinc-binding region that interact with pterin and stabilize the mNOS(ox) dimer.
Changes in patterns of residue conservation between bacterial and mammalian NOSs
correlate to different binding modes for pterin side chains. Residue
conservation on a surface patch surrounding an exposed heme edge indicates a
likely interaction site for reductase proteins in all NOSs. The heme pockets of
bsNOS and mNOS(ox) recognize L-Arg and NHA similarly, although a change from Val
to Ile beside the substrate guanidinium may explain the 10-20-fold slower
dissociation of product NO from the bacterial enzyme. Overall, these structures
suggest that bsNOS functions naturally to produce nitrogen oxides from L-Arg and
NHA in a pterin-dependent manner, but that the regulation and purpose of NO
production by NOS may be quite different in B. subtilis than in mammals.
|
|
|
|
|
|
|
