| Title | Structure of insoluble rat sperm glyceraldehyde-3-phosphate dehydrogenase via heterotetramer formation with E. coli glyceraldehyde-3-phosphate dehydrogenase reveals target for contraceptive design. | | Author(s) | Frayne J, Taylor A, Cameron G, Hadfield AT | | Institution | University of Bristol, United Kingdom. | | Source | J Biol Chem 2009 Jun 19. | | Abstract | Sperm glyceraldehyde-3-phosphate dehydrogenase has been shown to be a successful target for a non-hormonal contraceptive approach, but the agents tested to date have had unacceptable side-effects. Obtaining the structure of GAPDS to allow rational inhibitor design has therefore been a goal for a number of years but has proved intractable due to the insoluble nature of both native and recombinant protein. We have obtained soluble recombinant GAPDS as a heterotetramer with the E.coli GAPDH in a ratio of 1:3 and have solved the structure of the hetero-tetramer which we believe represents a novel strategy for structure determination of an insoluble protein. A structure was also obtained where glyceraldehyde-3-phosphate binds in the Ps pocket in the active site of the sperm enzyme subunit in the presence of NAD+. Modeling and comparison of the structures of GAPDS and Human somatic GAPDH revealed few differences at the active site, and hence rebut the long presumed structural specificity of 3-chlorolactaldehyde for GAPDS; the contraceptive activity of a-chlorohydrin and its apparent specificity for GAPDS in vivo likely due to differences in metabolism to 3-chlorolactaldehyde in spermatozoa and somatic cells. However, further detailed analysis of our GAPDS structure revealed sites in the enzyme that do show significant difference in the GAPDH structure that could alternatively be exploited by structure-based drug design for the identification of leads for novel male contraceptives. | | Language | ENG | | Pub Type(s) | JOURNAL ARTICLE
| | PubMed ID | 19542219 |
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