Isocitrate dehydrogenase from bovine heart: primary structure of subunit 3/4
| Autor: | P. Hsu, Jianmin Huang, Cipora Weiss, Linda Siconolfi-Baez, Tsai-Tse Yao, Julie Ivory Rushbrook, Yan Zeng |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 1995 |
| Předmět: |
Male
IDH1 DNA Complementary Macromolecular Substances Swine Protein subunit Molecular Sequence Data Saccharomyces cerevisiae Biology Biochemistry Peptide Mapping Polymerase Chain Reaction Sequence Homology Nucleic Acid Testis Escherichia coli Animals Amino Acid Sequence Molecular Biology Peptide sequence DNA Primers chemistry.chemical_classification Base Sequence Sequence Homology Amino Acid Myocardium Protein primary structure Cell Biology Haplorhini Molecular biology Isocitrate Dehydrogenase Recombinant Proteins Amino acid Rats Isocitrate dehydrogenase Enzyme chemistry Cattle NAD+ kinase Research Article |
| Popis: | Bovine NAD(+)-dependent isocitrate dehydrogenase was shown previously to contain four subunits of approx. 40 kDa (subunits 1-4) possessing different peptide maps and electrophoretic properties [Rushbrook and Harvey (1978) Biochemistry 17, 5339-5346]. In this study the heterogeneity is confirmed using enzyme purified by updated methods and from single animals, ruling out allelic variability. Subunits 1 and 2 were differentiated from each other and from subunits 3 and 4 by N-terminal amino acid sequencing. Subunits 3 and 4 (subunits 3/4) were identical in sequence over 30 residues. The N-terminal residues of subunits 1 and 2 were homologous but not identical with the beta- and gamma-subunits respectively of the comparable pig heart enzyme. Subunits 3/4 were identical over 30 residues with the N-terminus of the pig heart alpha-subunit. Full-length sequence, including that for mitochondrial import, is presented for a protein with the processed N-terminus of subunits 3/4, deduced from cloned cDNA obtained utilizing the N-terminal sequence information. The derived amino acid sequence for the mature protein contains 339 amino acids and has a molecular mass of 36,685 Da. Complete identity with N-terminal and Cys-containing peptides totalling 92 residues from the alpha-subunit of the pig heart enzyme [Huang and Colman (1990) Biochemistry 29, 8266-8273] suggests that maintenance of a particular three-dimensional structure in this subunit is crucial to the function of the enzyme. An electrophoretic heterogeneity within the pig heart alpha-subunit, similar to that shown by bovine subunits 3/4, was demonstrated. One reordering of the Cys-containing peptides of the pig heart alpha-subunit is indicated. Sequence comparison with the distantly related NADP(+)-dependent enzyme from Escherichia coli, for which the three-dimensional structure is known [Stoddard, Dean and Koshland (1993) Biochemistry 32, 9310-9316] shows strong conservation of residues binding isocitrate, Mg2+ and the NAD+ moiety of NADP+, consistent with a catalytic function. |
| Databáze: | OpenAIRE |
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