Complex between carboxypeptidase A and a possible transition-state analog: mechanistic inferences from high-resolution x-ray structures of enzyme-inhibitor complexes

1986 ◽  
Vol 108 (16) ◽  
pp. 4998-5003 ◽  
Author(s):  
David W. Christianson ◽  
William N. Lipscomb

Biochemistry ◽  
1989 ◽  
Vol 28 (15) ◽  
pp. 6294-6305 ◽  
Author(s):  
John E. Hanson ◽  
Alan P. Kaplan ◽  
Paul A. Bartlett


1992 ◽  
Vol 114 (8) ◽  
pp. 3165-3166 ◽  
Author(s):  
S. W. Fesik ◽  
P. Neri ◽  
R. Meadows ◽  
E. T. Olejniczak ◽  
G. Gemmecker


2015 ◽  
Vol 93 (6) ◽  
pp. 531-540 ◽  
Author(s):  
Robert W. Wheatley ◽  
Reuben E. Huber

When lactose was incubated with G794A-β-galactosidase (a variant with a “closed” active site loop that binds transition state analogs well) an allolactose was trapped with its Gal moiety in a 4H3 conformation, similar to the oxocarbenium ion-like conformation expected of the transition state. The numerous interactions formed between the 4H3 structure and β-galactosidase indicate that this structure is representative of the transition state. This conformation is also very similar to that of d-galactono-1,5-lactone, a good transition state analog. Evidence indicates that substrates take up the 4H3 conformation during migration from the shallow to the deep mode. Steric forces utilizing His418 and other residues are important for positioning the O1 leaving group into a quasi-axial position. An electrostatic interaction between the O5 of the distorted Gal and Tyr503 as well as C–H–π bonds with Trp568 are also significant. Computational studies of the energy of sugar ring distortion show that the β-galactosidase reaction itinerary is driven by energetic considerations in utilization of a 4H3 transition state with a novel 4C1-4H3-4C1 conformation itinerary. To our knowledge, this is the first X-ray crystallographic structural demonstration that the transition state of a natural substrate of a glycosidase has a 4H3 conformation.



2008 ◽  
Vol 26 (1) ◽  
pp. 153-157 ◽  
Author(s):  
Jing-Yi JIN ◽  
Shou-Feng WANG ◽  
Wei XUAN ◽  
Ji-Wen SHENG ◽  
Si-Hong WANG ◽  
...  




1996 ◽  
Vol 118 (10) ◽  
pp. 2340-2346 ◽  
Author(s):  
Michal Harel ◽  
Daniel M. Quinn ◽  
Haridasan K. Nair ◽  
Israel Silman ◽  
Joel L. Sussman


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