1D1S

WILD-TYPE HUMAN SIGMA (CLASS IV) ALCOHOL DEHYDROGENASE

Summary for 1D1S

• Entry DOI: 10.2210/pdb1d1s/pdb
• Related: 1AGN 1D1T
• Descriptor: ALCOHOL DEHYDROGENASE CLASS IV SIGMA CHAIN, ZINC ION, ACETATE ION, ... (6 entities in total)
• Functional Keywords: rossman or dinucleotide fold, oxidoreductase
• Biological source: Homo sapiens (human)
• Cellular location: Cytoplasm: P40394
• Total number of polymer chains: 4
• Total formula weight: 165046.40

Authors

Xie, P.T.,Hurley, T.D. (deposition date: 1999-09-21, release date: 1999-09-29, Last modification date: 2024-02-07)

Primary citation

Xie, P.T.,Hurley, T.D.
Methionine-141 directly influences the binding of 4-methylpyrazole in human sigma sigma alcohol dehydrogenase.
Protein Sci., 8:2639-2644, 1999

PubMed Abstract: Pyrazole and its 4-alkyl substituted derivatives are potent inhibitors for many alcohol dehydrogenases. However, the human sigma sigma isoenzyme exhibits a 580-fold lower affinity for 4-methylpyrazole than does the human beta1beta1 isoenzyme, with which it shares 69% sequence identity. In this study, structural and kinetic studies were utilized in an effort to identify key structural features that affect the binding of 4-methylpyrazole in human alcohol dehydrogenase isoenzymes. We have extended the resolution of the human sigma sigma alcohol dehydrogenase (ADH) isoenzyme to 2.5 A resolution. Comparison of this structure to the human beta1beta1 isoenzyme structure indicated that the side-chain position for Met141 in sigma sigma ADH might interfere with 4-methylpyrazole binding. Mutation of Met141 in sigma sigma ADH to Leu (sigma141L) lowers the Ki for 4-methylpyrazole from 350 to 10 microM, while having a much smaller effect on the Ki for pyrazole. Thus, the mutagenesis results show that the residue at position 141, which lines the substrate-binding pocket at a position close to the methyl group of 4-methylpyrazole, directly affects the binding of the inhibitor. To rule out nonspecific structural changes due to the mutation, the X-ray structure of the sigma141L mutant enzyme was determined to 2.4 A resolution. The three-dimensional structure of the mutant enzyme is identical to the wild-type enzyme, with the exception of the residue at position 141. Thus, the differences in 4-methylpyrazole binding between the mutant and wild-type sigma sigma ADH isoenzymes can be completely ascribed to the local changes in the topology of the substrate binding site, and provides an explanation for the class-specific differences in 4-methylpyrazole binding to the human ADH isoenzymes.

PubMed: 10631979

Experimental method

X-RAY DIFFRACTION (2.5 Å)