Contribution of Pro275 to the Thermostability of the Alcohol Dehydrogenases (2nvb)
(see also Tetrameric alcohol dehydrogenases)
Publication Abstract from PubMed
Analysis of the three-dimensional structures of two closely related thermophilic and hyperthermophilic alcohol dehydrogenases (ADHs) from the respective microorganisms Entamoeba histolytica (EhADH1) and Thermoanaerobacter brockii (TbADH) suggested that a unique, strategically located proline residue (Pro275) at the center of the dimerization interface might be crucial for maintaining the thermal stability of TbADH. To assess the contribution of Pro275 to the thermal stability of the ADHs, we applied site-directed mutagenesis to replace Asp275 of EhADH1 with Pro (D275P-EhADH1) and conversely Pro275 of TbADH with Asp (P275D-TbADH). The results indicate that replacing Asp275 with Pro significantly enhances the thermal stability of EhADH1 (DeltaT(1/2) </= +10 degrees C), whereas the reverse mutation in the thermophilic TbADH (P275D-TbADH) reduces the thermostability of the enzyme (DeltaT(1/2) </= -18.8 degrees C). Analysis of the crystal structures of the thermostabilized mutant D275P-EhADH1 and the thermocompromised mutant P275D-TbADH suggest that a proline residue at position 275 thermostabilized the enzymes by reducing flexibility and by reinforcing hydrophobic interactions at the dimer-dimer interface of the tetrameric ADHs. Proteins 2008. (c) 2008 Wiley-Liss, Inc.
Thermal stabilization of the protozoan Entamoeba histolytica alcohol dehydrogenase by a single proline substitution., Goihberg E, Dym O, Tel-Or S, Shimon L, Frolow F, Peretz M, Burstein Y, Proteins. 2008 Feb 7;. PMID:18260103
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
Ribbon diagram of the TbADH . Monomers are colored in different colors. Pro residues (ball representation) are colored orange (Pro275) which is important for thermal stabilization and cyan (Pro100). of the structures of the wild-type holo-TbADH (colored lime, 1ykf) and the holo P275D-TbADH mutant (colored orange) (2nvb). Pro275 and Asp275 are labeled red. Residues within a distance of 4Å from P275D are shown (names of subunits are in brackets). Nitrogen and oxygen atoms are colored in CPK colors. Replacing Pro275 with Asp reduces the thermal stability of the enzyme: ΔT1/260min = -13.8°C, ΔT1/2CD = -18.8°C. 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.
About this Structure
2NVB is a Single protein structure of sequence from Thermoanaerobacter brockii. Full crystallographic information is available from OCA.
Reference
Thermal stabilization of the protozoan Entamoeba histolytica alcohol dehydrogenase by a single proline substitution., Goihberg E, Dym O, Tel-Or S, Shimon L, Frolow F, Peretz M, Burstein Y, Proteins. 2008 Feb 7;. PMID:18260103
