Alcohol dehydrogenase from Entamoeba histolytica
From Proteopedia
 Alcohol Dehydrogenase from Entamoeba histolotica (EhADH1)(see also Tetrameric alcohol dehydrogenases)
Publication Abstract from PubMed
The structure of the apo form of alcohol dehydrogenase from a single-cell eukaryotic source, Entamoeba histolytica, has been determined at 1.8 A. To date, bacterial and archeal alcohol dehydrogenases, which are biologically active as tetramers, have crystallized with tetramers in the asymmetric unit. However, the current structure has one independent dimer per asymmetric unit and the full tetramer is generated by application of the crystallographic twofold symmetry element. This structure reveals that many of the crystallization and cryoprotection components, such as cacodylate, ethylene glycol, zinc ions and acetate, have been incorporated. These crystallization solution elements are found within the molecule and at the packing interfaces as an integral part of the three-dimensional arrangements of the tetramers. In addition, an unexpected modification of aspartic acid to O-carboxysulfanyl-4-oxo-L-homoserine was found at residue 245. Structure of alcohol dehydrogenase from Entamoeba histolytica., Shimon LJ, Goihberg E, Peretz M, Burstein Y, Frolow F, Acta Crystallogr D Biol Crystallogr. 2006 May;62(Pt 5):541-7. Epub 2006, Apr 19. PMID:16627948 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. of the structures of the wild-type apo-EhADH1 (alcohol dehydrogenase from Entamoeba histolotica, colored lime, 1y9a) and the apo D275P-EhADH1 mutant (colored orange) (2oui). Pro275 and Asp275 are labeled red. Residues within a distance of 4 Å from the mutation are shown (names of monomers are in brackets). Replacing with significantly enhanced the thermal stability of EhADH1: ΔT1/260min = +9.3°C, ΔT1/2CD = +10°C. The reverse mutation in the thermophilic alcohol dehydrogenase from Thermoanaerobacter brockii (1ykf; colored magenta) - substitution of wt TbADH Pro275 with (2nvb; colored cyan) reduced the thermal stability of the enzyme: ΔT1/260min = -13.8°C, ΔT1/2CD = -18.8°C. Nitrogen and oxygen atoms are colored in CPK colors. Pro275 and Asp275 are labeled red (names of monomers are in brackets). These findings indicate that a single proline mutation is responsible for the significant differences in the thermal stability of ADHs, and show the importance of prolines in the protein stability. It was also shown that substitution by proline at the important positions could significantly stabilize the protein. About this Structure1Y9A is a 2 chains structure of sequences from Entamoeba histolytica. Full crystallographic information is available from OCA. Reference
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