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Mobile sequences in the pyruvate dehydrogenase complex, the E 2 component, the catalytic domain and the 2‐oxoglutarate dehydrogenase complex of Azotobacter vinelandii , as detected by 600 MHz 1 H‐NMR spectroscopy
Author(s) -
Hanemaaijer Roeland,
Vervoort Jacques,
Westphal Adrie H.,
de Kok Arie,
Veeger Cees
Publication year - 1988
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(88)80369-7
Subject(s) - azotobacter vinelandii , chemistry , pyruvate dehydrogenase complex , oxoglutarate dehydrogenase complex , histidine , nuclear magnetic resonance spectroscopy , stereochemistry , dihydrolipoyl transacetylase , alanine , dehydrogenase , crystallography , biochemistry , pyruvate dehydrogenase kinase , pyruvate dehydrogenase phosphatase , enzyme , amino acid , nitrogenase , organic chemistry , nitrogen fixation , nitrogen
600 MHz 1 H‐NMR spectroscopy demonstrates that the pyruvate dehydrogenase complex of Azotobacter vinelandii contains regions of the polypeptide chain with intramolecular mobility. This mobility is located in the E 2 component and can probably be ascribed to alanine‐proline‐rich regions that link the lipoyl subdomains to each other as well as to the E 1 and E 3 binding domain. In the catalytic domain of E 2 , which is thought to form a compact, rigid core, also conformational flexibility is observed. It is conceivable that the N‐terminal region of the catalytic domain, which contains many alanine residues, is responsible for the observed mobility. In the low‐field region of the 1 H‐NMR spectrum of E 2 specific resonances are found, which can be ascribed to mobile phenylalanine, histidine and/or tyrosine residues which are located in the E 1 and E 3 binding domain that links the lipoyl domain to the catalytic domain. In the 1 H‐NMR spectrum of the intact complex, these resonances cannot be observed, indicating a decreased mobility of the E 1 and E 3 binding domain.