NMR study of structure and electron transfer mechanism of Pseudomonas aeruginosa azurin

Journal Article · Tue Jan 05 04:00:00 EST 1988 · J. Biol. Chem.; (United States)

OSTI ID:6770442

Groeneveld, C M; Canters, G W

The nuclear spin-spin and spin-lattice relaxation times of the C/sub epsilon 1/-proton of His-35 and the C/sub delta2/-proton of His-46 of reduced Pseudomonas aeruginosa azurin have been determined at 298 and 320 K and at pH 4.5 and 9.0 at various concentrations of total azurin and in the presence of varying amounts of oxidized azurin. The relaxation times appear strongly influenced by the electron self-exchange reaction between oxidized and reduced protein. The T/sub 1/ data of the His-35 proton have been analyzed accorindg to the fast-exchange limit, while the slow-exchange limit appears to obtain for the T/sub 2/ data of the His-46 proton. The dipolar correlation time amounts to 1-2.5 ns in the temperature range of 298-320 K. A Fermi-contact interaction of about 100 mG for the C/sub delta2/-proton of His-46 is compatible with the experimental observations. The pH-induced conformational changes lead to variations on the order of about 1 A in the distance from the copper to the His-35 protons. The data implicate the hydrophobic patch around His-117 as the site of electron transfer in the self-exchange reaction of the azurin.

• Research Organization: Leiden Univ. (Netherlands)
• OSTI ID: 6770442
• Journal Information: J. Biol. Chem.; (United States), Journal Name: J. Biol. Chem.; (United States) Vol. 263:1; ISSN JBCHA
• Country of Publication: United States
• Language: English

Related Subjects

550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
AMINO ACIDS
AZOLES
BACTERIA
BARYONS
CARBOXYLIC ACIDS
ELECTRON TRANSFER
ELEMENTARY PARTICLES
FERMIONS
HADRONS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HISTIDINE
IMIDAZOLES
MAGNETIC RESONANCE
METALLOPROTEINS
MICROORGANISMS
NUCLEAR MAGNETIC RESONANCE
NUCLEONS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PROTEINS
PROTONS
PSEUDOMONAS
RELAXATION
RESONANCE
SPIN-LATTICE RELAXATION
SPIN-SPIN RELAXATION