A STRUCTURE-REACTIVITY STUDY OF THE BINDING OF ACETYLGLUTAMATE TO CARBAMOYL PHOSPHATE SYNTHETASE-I

被引:14
作者
BRITTON, HG
GARCIAESPANA, A
GOYA, P
ROZAS, I
RUBIO, V
机构
[1] INST INVEST CITOL CAJA AHORROS VALENCIA,AMADEO SABOYA 4,E-46010 VALENCIA,SPAIN
[2] ST MARYS HOSP,SCH MED,DEPT PHYSIOL,LONDON,ENGLAND
[3] CSIC CTR,INST QUIM MED,MADRID,SPAIN
来源
EUROPEAN JOURNAL OF BIOCHEMISTRY | 1990年 / 188卷 / 01期
关键词
D O I
10.1111/j.1432-1033.1990.tb15369.x
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
The requirements for binding at the N‐acetyl‐L‐glutamate binding site of carbamoyl phosphate synthetase I were studied by the displacement of the activator from the central enzyme complex by analogs. Two carboxyls are essential and the acetamido group, if linked to the α‐carbon, enhances binding 5000‐fold. the subsite for the δ‐carboxyl is mobile with respect to that for the α‐carboxyl. Mixtures of complementary fragment of acetylglutamate do not bind, inidicating a strong ‘chelate’ effect. Substituents revealed the existence of steric constraints around the δ‐carboxyl, the α and γ‐carbons, and the whole of the acetamido group. However, phenyl substituents at the β‐carbon did not hamper binding, indicating that substituents at the β‐carbon face the solution. This is consistent with binding of acetylglutamate as the minimum‐energy conformer. All analogs binding with high affinity are activators. Some analogs that bind poorly are competitive inhibitors. They appear to bind preferentially to a low‐affinity conformation adopted by the site when the products dissociate and the substrates bind. The acetamido group plays no role in the binding of the binding of the inhibitors but it is crucial for the binding of the activators, and the high‐and low‐affinity conformations of the site differ markedly in structural selectivity. Copyright © 1990, Wiley Blackwell. All rights reserved
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页码:47 / 53
页数:7
相关论文
共 36 条
[1]   STUDIES ON FUNCTION OF N-ACYL GLUTAMATES IN CARBAMYL PHOSPHATE SYNTHETASE REACTION [J].
ALLEN, CM ;
JONES, ME .
ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS, 1966, 114 (01) :115-&
[2]   CAMBRIDGE CRYSTALLOGRAPHIC DATA CENTER - COMPUTER-BASED SEARCH, RETRIEVAL, ANALYSIS AND DISPLAY OF INFORMATION [J].
ALLEN, FH ;
BELLARD, S ;
BRICE, MD ;
CARTWRIGHT, BA ;
DOUBLEDAY, A ;
HIGGS, H ;
HUMMELINK, T ;
HUMMELINKPETERS, BG ;
KENNARD, O ;
MOTHERWELL, WDS ;
RODGERS, JR ;
WATSON, DG .
ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE, 1979, 35 (OCT) :2331-2339
[3]   INACTIVATION OF MITOCHONDRIAL CARBAMOYL PHOSPHATE SYNTHETASE INDUCED BY ASCORBATE, OXYGEN, AND FE-3+ IN THE PRESENCE OF ACETYLGLUTAMATE - PROTECTION BY ATP AND HCO3- AND LACK OF INACTIVATION OF ORNITHINE TRANSCARBAMYLASE [J].
ALONSO, E ;
RUBIO, V .
ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS, 1987, 258 (02) :342-350
[4]   BINDING OF N-ACETYL-L-GLUTAMATE TO RAT-LIVER CARBAMOYL PHOSPHATE SYNTHETASE (AMMONIA) [J].
ALONSO, E ;
RUBIO, V .
EUROPEAN JOURNAL OF BIOCHEMISTRY, 1983, 135 (02) :331-337
[5]  
ALONSO E, 1986, THESIS U VALENCIA
[6]   CARBAMOYL-PHOSPHATE SYNTHETASE-I - KINETICS OF BINDING AND DISSOCIATION OF ACETYLGLUTAMATE AND OF ACTIVATION AND DEACTIVATION [J].
BRITTON, HG ;
RUBIO, V .
EUROPEAN JOURNAL OF BIOCHEMISTRY, 1988, 171 (03) :615-622
[7]   MECHANISM OF CARBAMOYL-PHOSPHATE SYNTHETASE - PROPERTIES OF THE 2 BINDING-SITES FOR ATP [J].
BRITTON, HG ;
RUBIO, V ;
GRISOLIA, S .
EUROPEAN JOURNAL OF BIOCHEMISTRY, 1979, 102 (02) :521-530
[8]  
Cleland W W, 1979, Methods Enzymol, V63, P103
[9]  
COHEN PP, 1950, J BIOL CHEM, V182, P747
[10]   THE DEVELOPMENT AND USE OF QUANTUM-MECHANICAL MOLECULAR-MODELS .76. AM1 - A NEW GENERAL-PURPOSE QUANTUM-MECHANICAL MOLECULAR-MODEL [J].
DEWAR, MJS ;
ZOEBISCH, EG ;
HEALY, EF ;
STEWART, JJP .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1985, 107 (13) :3902-3909