Structure of the SHV-1 beta-lactamase.
The X-ray crystallographic structure of the SHV-1 beta-lactamase has been established. The enzyme crystallizes from poly(ethylene glycol) at pH 7 in space group P212121 with cell dimensions a = 49.6 A, b = 55.6 A, and c = 87.0 A. The structure was solved by the molecular replacement method, and the model has been refined to an R-factor of 0.18 for all data in the range 8.0-1.98 A resolution. Deviations of model bonds and angles from ideal values are 0.018 A and 1.8 degrees, respectively. Overlay of all 263 alpha-carbon atoms in the SHV-1 and TEM-1 beta-lactamases results in an rms deviation of 1.4 A. Largest deviations occur in the H10 helix (residues 218-224) and in the loops between strands in the beta-sheet. All atoms in residues 70, 73, 130, 132, 166, and 234 in the catalytic site of SHV-1 deviate only 0.23 A (rms) from atoms in TEM-1. However, the width of the substrate binding cavity in SHV-1, as measured from the 104-105 and 130-132 loops on one side to the 235-238 beta-strand on the other side, is 0.7-1.2 A wider than in TEM-1. A structural analysis of the highly different affinity of SHV-1 and TEM-1 for the beta-lactamase inhibitory protein BLIP focuses on interactions involving Asp/Glu104.
Kuzin
A P
AP
Department of Molecular and Cell Biology, The University of Connecticut, Storrs 06269-3125, USA.
Nukaga
M
M
Nukaga
Y
Y
Hujer
A M
AM
Bonomo
R A
RA
Knox
J R
JR
D000595:Amino Acid Sequence; D001665:Binding Sites; D003460:Crystallization; D003902:Detergents / Q000737:chemistry; D007711:Klebsiella pneumoniae / Q000201:enzymology; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D001618:beta-Lactamases / Q000737:chemistry*
D003902:Detergents; C054882:beta-lactamase PIT-2; D001618:beta-Lactamases