Three-dimensional structures citrate synthase

Figure 13-8 Three-dimensional structure of citrate synthase. (A) Stereoscopic alpha carbon trace of the dimeric pig enzyme in its open conformation.209 A molecule of citrate is shown in the lower subunit. The view is down the two-fold axis. Courtesy of Robert Huber.

Thiosulfate cyanide sulfurtransferase symmetry in 78 TTiiouridine 234 Three-dimensional structures of aconitase 689 adenylate kinase 655 aldehyde oxido-reductase 891 D-amino acid oxidase 791 a-amylase, pancreatic 607 aspartate aminotransferase 57,135 catalytic intermediates 752 aspartate carbamyltransferase 348 aspartate chemoreceptor 562 bacteriophage P22 66 cadherin 408 calmodulin 317 carbonic acid anhydrase I 679 carboxypeptidase A 64 catalase 853 cholera toxin 333, 546 chymotrypsin 611 citrate synthase 702, 703 cutinase 134 cyclosporin 488 cytochrome c 847 cytochrome c peroxidase 849 dihydrofolate reductase 807 DNA 214, 223,228,229, 241 DNA complex... 

The use of X-ray techniques to elucidate the three-dimensional structure of enzymes shows that many of them possess a characteristic concave cleft at the active site. Concavities of this type have been observed, for example, in the case of lysozyme [8, 9] trypsin [10], yeast hexokinase [11], liver alcohol dehydrogenase [12] and citrate synthase [13]. It is thus reasonable to assume that the interaction between an enzyme and its substrate, inhibitor or cofactor usually occurs not in bulk water but rather in a shielded proteic cleft whose specific microenvironment is induced by the amino acid residues forming the cleft. Hydrophobicity, electrostatics, solvation and a relatively low dielectric constant prevailing within the cleft no doubt play a decisive role in determining the nature and rate of the reaction catalyzed by the enzyme. 

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See also in sourсe #XX -- [ , ]

See also in sourсe #XX -- [ , ]

See also in sourсe #XX -- [ , ]

See also in sourсe #XX -- [ , ]

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