Proton and tritium NMR relaxation studies of peptide inhibitor binding to bacterial collagenase: Conformation and dynamics

Journal Article · Fri Feb 15 00:00:00 EST 1991 · Biopolymers; (United States)

DOI:https://doi.org/10.1002/bip.360310305· OSTI ID:5266626

Dive, V; Lai, A; Valensin, G; Saba, G; Yiotakis, A; Toma, F ^[1]

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1. Service de Biochimie, Laboratoire d'Ingenierie des Proteines, CEN-Saclay (France)

The interaction of succinyl-Pro-Ala, a competitive inhibitor of Achromobacter iophagus collagenase, with the enzyme was studied by longitudinal proton and tritium relaxation. Specific deuterium and tritium labeling of the succinyl part at vicinal positions allowed the measurement of the cross-relaxation rates of individual proton or tritium spin pairs in the inhibitor-enzyme complex as well as in the free inhibitor. Overall correlation times, internuclear distances, and qualitative information on the internal mobility in Suc1 (as provided by the generalized order parameter S2) could be deduced by the comparison of proton and tritium cross-relaxation of spin pairs at complementary positions in the -CH2- CH2- moiety as analyzed in terms of the model-free approach by Lipari and Szabo. The conformational and motional parameters of the inhibitor in the free and enzyme-bound state were directly compared by this method. The measurement of proton cross-relaxation in the Ala residue provided additional information on the inhibitor binding. The determination of the order parameter in different parts of the inhibitor molecule in the bound state indicates that the succinyl and alanyl residues are primarily involved in the interaction with the enzyme activity site. The succinyl moiety, characterized in solution by the conformational equilibrium among the three staggered rotamers--i.e., trans: 50%; g+: 20%; g-: 30%--adopted in the bound state the unique trans conformation.

• OSTI ID: 5266626
• Journal Information: Biopolymers; (United States), Vol. 31:3; ISSN 0006-3525
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
ENZYME INHIBITORS
MOLECULAR STRUCTURE
AMINO ACID SEQUENCE
CLOSTRIDIUM
DEUTERIUM
NUCLEAR MAGNETIC RESONANCE
PEPTIDE HYDROLASES
PROTONS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
BACTERIA
BARYONS
ELEMENTARY PARTICLES
ENZYMES
FERMIONS
HADRONS
HYDROGEN COMPOUNDS
HYDROGEN ISOTOPES
HYDROLASES
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
MAGNETIC RESONANCE
MICROORGANISMS
NUCLEI
NUCLEONS
ODD-ODD NUCLEI
RESONANCE
STABLE ISOTOPES
550201* - Biochemistry- Tracer Techniques