Characterization of the bait region and zinc binding sites of human alpha-2-macroglobulin by /sup 1/H and /sup 35/Cl NMR

Conference · Thu May 01 00:00:00 EDT 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:7246520

Gettins, P; Cunningham, L W

Human ..cap alpha../sub 2/ macroglobulin (..cap alpha../sub 2/M) is a zinc metalloprotein that possesses anti-protease activity towards a wide range of proteases. It is a tetramer of molecular weight 718,000 daltons. Proteases cleave ..cap alpha../sub 2/M in the bait region and cause a large-scale conformational change which traps the protease. The present studies are aimed at elucidating the details of the steps involved in protease binding, cleavage and ..cap alpha../sub 2/M rearrangement. /sup 1/H NMR of ..cap alpha../sub 2/M shows 9 well resolved aromatic region resonances. These are all perturbed by protease cleavage and have all been assigned to residues in the bait region. This is part of a 35 amino acid region of high surface mobility. The resonances arise from tyr685, phe684, and histidines 675, 694, 699 and 704. Methylamine reacts with ..cap alpha../sub 2/M to cause the same conformational change as with proteases but doesn't cleave the bait region. The /sup 1/H resonances from the bait region are not affected by methylamine reaction. /sup 35/Cl NMR has been used to follow zinc binding to apo-..cap alpha../sub 2/M. ..cap alpha../sub 2/M possesses a unique pair of high affinity zinc sites, which may be involved in subunit association. Other weaker sites exist. Reaction with methylamine reduces the affinity of the weaker sites. Manganese can replace zinc and will be a useful probe for distance measurements.

• Research Organization: Vanderbilt Univ. School of medicine, Nashville, TN
• OSTI ID: 7246520
• Report Number(s): CONF-8606151-
• Journal Information: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Vol. 45:6; ISSN FEPRA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
550600 -- Medicine
59 BASIC BIOLOGICAL SCIENCES
62 RADIOLOGY AND NUCLEAR MEDICINE
AFFINITY
ANIMALS
BIOCHEMICAL REACTION KINETICS
CHLORINE 35
CHLORINE ISOTOPES
CLEAVAGE
CRYSTAL STRUCTURE
ELEMENTS
ENZYMES
GLOBULINS
GLOBULINS-ALPHA
HYDROLASES
ISOTOPES
KINETICS
LIGHT NUCLEI
MAGNETIC RESONANCE
MAMMALS
MAN
MEMBRANE PROTEINS
METALS
MICROSTRUCTURE
MOLECULAR WEIGHT
NMR SPECTRA
NUCLEAR MAGNETIC RESONANCE
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PEPTIDE HYDROLASES
PRIMATES
PROTEIN STRUCTURE
PROTEINS
REACTION KINETICS
RECEPTORS
RESONANCE
SPECTRA
STABLE ISOTOPES
VERTEBRATES
ZINC