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Structure of Potato Inhibitor Complex of Carboxypeptidase A at 5.5Å Resolution

Rees, Douglas C. and Lipscomb, William N. (1980) Structure of Potato Inhibitor Complex of Carboxypeptidase A at 5.5Å Resolution. Proceedings of the National Academy of Sciences of the United States of America, 77 (1). pp. 277-280. ISSN 0027-8424. PMCID PMC348252. doi:10.1073/pnas.77.1.277.

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The complex of the 39-amino inhibitor (potato) of bovine carboxypeptidase A (carboxypeptidase; peptidyl-L-amino-acid hydrolase, EC was crystallized in space group P3_2. There are two protein-inhibitor complexes in the asymmetric unit. These crystals exhibited pseudo-P32_21 symmetry due to twinning about the a_3 axis. Heavy atom difference Patterson maps and rotation functions indicated, however, that the noncrystallographic twofold axis that relates these two complexes is nearly coincident with the a_3 axis. Consequently, to a good approximation at low resolution, the space group of the complex is P3_221 and the effects of twinning may be ignored. The structure was solved by using multiple isomorphous replacement and molecular replacement techniques. At 5.5-Å resolution, the multiple isomorphous replacement map was readily interpretable in terms of the known native carboxypeptidase A structure plus extra density around the active site. The position of this extra density is consistent with the binding mode for extended substrate proposed from earlier model building studies with the native enzyme (Lipscomb, W.N., Hartsuck, J.A., Reeke, G.N., Quiocho, F.A. Bethge, P.H., Ludwig, M.L., Steitz, T.A., Muirhead, H. & Coppola, J.C. (1968) Brookhaven Symp. Biol. 21, 24-90).

Item Type:Article
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URLURL TypeDescription CentralArticle
Rees, Douglas C.0000-0003-4073-1185
Additional Information:© 1980 National Academy of Sciences. Contributed by William N. Lipscomb, October 18, 1979. We thank H. Wyckoff for advice on data collection and the National Institutes of Health (Grant GM 06920) for support. The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S. C. §1734 solely to indicate this fact.
Funding AgencyGrant Number
NIHGM 06920
Subject Keywords:enzyme complex; protease inhibitors; protein crystallography
Issue or Number:1
PubMed Central ID:PMC348252
Record Number:CaltechAUTHORS:20150210-100728083
Persistent URL:
Official Citation:D C Rees and W N Lipscomb Structure of potato inhibitor complex of carboxypeptidase A at 5.5-A resolution PNAS 1980 77 (1) 277-280
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:54659
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Deposited On:10 Feb 2015 20:36
Last Modified:10 Nov 2021 20:36

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