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Titolo:
PROTON NMR INVESTIGATION OF THE [4FE-4S](1-VINELANDII - DEFINING NUCLEOTIDE-INDUCED CONFORMATIONAL-CHANGES() CLUSTER ENVIRONMENT OF NITROGENASE IRON PROTEIN FROM AZOTOBACTER)
Autore:
LANZILOTTA WN; HOLZ RC; SEEFELDT LC;
Indirizzi:
UTAH STATE UNIV,DEPT CHEM & BIOCHEM LOGAN UT 84322 UTAH STATE UNIV,DEPT CHEM & BIOCHEM LOGAN UT 84322
Titolo Testata:
Biochemistry
fascicolo: 48, volume: 34, anno: 1995,
pagine: 15646 - 15653
SICI:
0006-2960(1995)34:48<15646:PNIOT[>2.0.ZU;2-P
Fonte:
ISI
Lingua:
ENG
Soggetto:
ELECTRON-PARAMAGNETIC-RESONANCE; CLOSTRIDIUM-PASTEURIANUM; FE-PROTEIN; MAGNETIC-RESONANCE; ADENOSINE 5'-TRIPHOSPHATE; AZOFERREDOXIN; METALLOCLUSTERS; FERREDOXIN; COMPONENT; MOSSBAUER;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
46
Recensione:
Indirizzi per estratti:
Citazione:
W.N. Lanzilotta et al., "PROTON NMR INVESTIGATION OF THE [4FE-4S](1-VINELANDII - DEFINING NUCLEOTIDE-INDUCED CONFORMATIONAL-CHANGES() CLUSTER ENVIRONMENT OF NITROGENASE IRON PROTEIN FROM AZOTOBACTER)", Biochemistry, 34(48), 1995, pp. 15646-15653

Abstract

This work presents the complete assignment of the isotropically shifted H-1 NMR resonances of Azotobacter vinelandii nitrogenase iron protein (Fe protein) to beta-CH2 and alpha-CH protons of the [4Fe-4S](1+) cluster cysteinyl ligands. Four resonances were observed for the reduced Fe protein with chemical shifts of 49, 23, 17, and 13 ppm. T-l measurements and analysis of relative peak areas coupled with one-dimensional nuclear Overhauser effect (NOE) difference spectra were used to assign the two most downfield-shifted resonances (49 and 23 ppm) to cysteinyl ligand beta-CH2 protons and the 17 and 14 ppm resonances to cysteinyl ligand alpha-CH protons. Temperature dependence studies of the isotropically shifted protons revealed both Curie and anti-Curie behavior. These results, along with previous Mossbauer studies of the Fe protein, allowed the assignment of signal A (49 ppm) to four beta-CH2 protons and signal C (17 ppm) to 2 alpha-CH protons of two cysteinyl ligands bound to a mixed-valence iron pair (Fe3+-Fe2+) of the [4Fe-4S](1+) cluster. Signal B (23 ppm) was assigned to four beta-CH2 protons, and signal C (17 ppm) and D (13 ppm) were assigned to two alpha-CH protonsof two cysteinyl ligands bound to a ferrous pair of irons (2Fe(2+)). The effects of MgATP, MgADP, and Mg-adenosine-beta, gamma-methylene-5'-triphosphate binding to the Fe protein on the assigned resonances were established and are discussed in the context of nucleotide-induced changes in the protein environment of the [4Fe-4S] cluster. In addition, conditions are described that prevent the long-standing problem of A, vinelandii Fe protein self-oxidation.

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Documento generato il 01/12/20 alle ore 19:30:40