Crystal structures of an oligopeptide-binding protein from the biosynthetic pathway of the beta-lactamase inhibitor clavulanic acid.
Clavulanic acid (CA) is a clinically important beta-lactamase inhibitor that is produced by fermentation of Streptomyces clavuligerus. The CA biosynthesis pathway starts from arginine and glyceraldehyde-3-phosphate and proceeds via (3S,5S)-clavaminic acid, which is converted to (3R,5R)-clavaldehyde, the immediate precursor of (3R,5R)-CA. Open reading frames 7 (orf7) and 15 (orf15) of the CA biosynthesis cluster encode oligopeptide-binding proteins (OppA1 and OppA2), which are essential for CA biosynthesis. OppA1/2 are proposed to be involved in the binding and/or transport of peptides across the S. clavuligerus cell membrane. Peptide binding assays reveal that recombinant OppA1 and OppA2 bind di-/tripeptides containing arginine and certain nonapeptides including bradykinin. Crystal structures of OppA2 in its apo form and in complex with arginine or bradykinin were solved to 1.45, 1.7, and 1.7 A resolution, respectively. The overall fold of OppA2 consists of two lobes with a deep cavity in the center, as observed for other oligopeptide-binding proteins. The large cavity creates a peptide/arginine binding cleft. The crystal structures of OppA2 in complex with arginine or bradykinin reveal that the C-terminal arginine of bradykinin binds similarly to arginine. The results are discussed in terms of the possible roles of OppA1/2 in CA biosynthesis.
Mackenzie
Alasdair K
AK
Department of Molecular Biology, Swedish University of Agricultural Sciences, Uppsala, Sweden.
Valegård
Karin
K
Iqbal
Aman
A
Caines
Matthew E C
ME
Kershaw
Nadia J
NJ
Jensen
Susan E
SE
Schofield
Christopher J
CJ
Andersson
Inger
I
D001120:Arginine / Q000737:chemistry / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D002352:Carrier Proteins / Q000737:chemistry* / Q000378:metabolism; D020134:Catalytic Domain; D019818:Clavulanic Acid / Q000096:biosynthesis*; D018360:Crystallography, X-Ray; D008074:Lipoproteins / Q000737:chemistry* / Q000378:metabolism; D053858:Metabolic Networks and Pathways / Q000502:physiology; D008958:Models, Molecular; D011485:Protein Binding; D011487:Protein Conformation; D013302:Streptomyces / Q000201:enzymology / Q000378:metabolism; D065093:beta-Lactamase Inhibitors
D001426:Bacterial Proteins; D002352:Carrier Proteins; D008074:Lipoproteins; D065093:beta-Lactamase Inhibitors; C046506:oligopeptide-binding protein, bacteria; D019818:Clavulanic Acid; D001120:Arginine