TO BUILD AN ENZYME

被引:74
作者
KNOWLES, JR [1 ]
机构
[1] HARVARD UNIV,DEPT BIOCHEM,CAMBRIDGE,MA 02138
关键词
D O I
10.1098/rstb.1991.0039
中图分类号
Q [生物科学];
学科分类号
07 ; 0710 ; 09 ;
摘要
The structural components that lead to enzyme function are discussed for one simple enzyme-catalysed reaction: that mediated by triosephosphate isomerase. First, the recognition and binding of the substrates' phospho group is seen to involve four main-chain-NH-hydrogen bonds, two of which are positioned at the positive end of a short alpha-helix aimed precisely at the phospho group and interact with the three peripheral phospho group oxygens. Second, the chemical steps (of substrates enolization) are shown to require both base and general acid catalysis. The identity and the positioning of the base, a carboxylate group, nicely fulfils the expectations both of mechanistic economy and of stereoelectronics. The identity of the general acid is shown by Fourier transform infrared and by N-15 nuclear magnetic resonance (NMR) to be a neutral imidazole group, lying between the two substrate oxygens. The positioning of the ring is ideal, but its protonation state is unexpected. Thus the pK(a) of this histidine side-chain is < 4.5, lowered from 6.5 (the value in the denatured protein) by its position at the positive end of another well-aimed alpha-helix. Third, the need for enzymes to provide kinetic barriers to the loss of reaction intermediates from the active site is emphasized. Triosephosphate isomerase achieves this sequestration of the reaction intermediate by using a flexible loop of the protein, and thus improves the efficiency of the catalysed transformation.
引用
收藏
页码:115 / 121
页数:7
相关论文
共 39 条
[1]  
ALBER T, 1981, PHIL T R SOC LOND B, V293, P169
[3]   STRUCTURE OF CHICKEN MUSCLE TRIOSE PHOSPHATE ISOMERASE DETERMINED CRYSTALLOGRAPHICALLY AT 2.5A RESOLUTION USING AMINO-ACID SEQUENCE DATA [J].
BANNER, DW ;
BLOOMER, AC ;
PETSKO, GA ;
PHILLIPS, DC ;
POGSON, CI ;
WILSON, IA ;
CORRAN, PH ;
FURTH, AJ ;
MILMAN, JD ;
OFFORD, RE ;
PRIDDLE, JD ;
WALEY, SG .
NATURE, 1975, 255 (5510) :609-614
[4]   CRITICAL IONIZATION STATES IN REACTION CATALYZED BY TRIOSEPHOSPHATE ISOMERASE [J].
BELASCO, JG ;
HERLIHY, JM ;
KNOWLES, JR .
BIOCHEMISTRY, 1978, 17 (15) :2971-2978
[5]   DIRECT OBSERVATION OF SUBSTRATE DISTORTION BY TRIOSEPHOSPHATE ISOMERASE USING FOURIER-TRANSFORM INFRARED-SPECTROSCOPY [J].
BELASCO, JG ;
KNOWLES, JR .
BIOCHEMISTRY, 1980, 19 (03) :472-477
[6]   HOW CAN A CATALYTIC LESION BE OFFSET - THE ENERGETICS OF 2 PSEUDOREVERTANT TRIOSEPHOSPHATE ISOMERASES [J].
BLACKLOW, SC ;
KNOWLES, JR .
BIOCHEMISTRY, 1990, 29 (17) :4099-4108
[7]   STUDIES OF HISTIDINE RESIDUES OF TRIOSE PHOSPHATE ISOMERASE BY PROTON MAGNETIC-RESONANCE AND X-RAY CRYSTALLOGRAPHY [J].
BROWNE, CA ;
CAMPBELL, ID ;
KIENER, PA ;
PHILLIPS, DC ;
WALEY, SG ;
WILSON, IA .
JOURNAL OF MOLECULAR BIOLOGY, 1976, 100 (03) :319-343
[8]   IMIDAZOLE CATALYSIS .2. THE REACTION OF SUBSTITUTED IMIDAZOLES WITH PHENYL ACETATES IN AQUEOUS SOLUTION [J].
BRUICE, TC ;
SCHMIR, GL .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1958, 80 (01) :148-156
[9]   FORM OF 2-PHOSPHOGLYCOLLIC ACID BOUND BY TRIOSEPHOSPHATE ISOMERASE [J].
CAMPBELL, ID ;
JONES, RB ;
KIENER, PA ;
RICHARDS, E ;
WALEY, SG ;
WOLFENDEN, R .
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, 1978, 83 (01) :347-352
[10]  
COLLINS KD, 1974, J BIOL CHEM, V249, P136