NMr studies of the AMP binding site and mechanism of adenylate kinase
The authors recently located by NMR the MgATP binding site on adenylate kinase correcting the proposed location for this site based on X-ray studies of the binding of salicylate. To determine the conformation and location of the other substrate, they have determined distances from Cr/sup 3 +/ AMPPCP to 6 protons and to the phosphorus atom of AMP on adenylate kinase using the paramagnetic-probe-T/sub 1/ method. They have also used time-dependent NOEs to measure five interproton distances on AMP, permitting evaluation of the conformation of enzyme-bound AMP and its position with respect to metal-ATP. Enzyme-bound AMP exhibits a high-anti glycosyl torsional angle (X = 110/sup 0/), a 3'-endo sugar pucker (delta = 105/sup 0/), and a gauche-trans orientation about the C/sub 4/'-C/sub 5/' bond (..gamma.. = 180/sup 0/). The distance from Cr/sup 3 +/ to the phosphorus of AMP is 6.4 +/- 0.3 A, indicating a reaction coordinate distance of greater than or equal to A which is consistent with an associative SN2 mechanism for the phosphoryl transfer. Ten intermolecular NOEs, from protons of the enzyme to those of AMP were detected. These constraints, together with the conformation of AMP and the X-ray structure of the enzyme, suggest proximity (less than or equal to A) of AMP to leu 116, arg 171, val 173, gln 185, thr 188, and asp 191.
- Research Organization:
- Univ. of Utah, Salt Lake City
- OSTI ID:
- 5232852
- 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
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Related Subjects
550600* -- Medicine
59 BASIC BIOLOGICAL SCIENCES
62 RADIOLOGY AND NUCLEAR MEDICINE
AMP
BARYONS
CARBOXYLIC ACIDS
CATIONS
CHARGED PARTICLES
CHROMIUM COMPOUNDS
ELEMENTARY PARTICLES
ENZYMES
FERMIONS
GLYCERIC ACID
HADRONS
HYDROXY ACIDS
IONS
MEMBRANE PROTEINS
MOLECULAR STRUCTURE
NMR SPECTRA
NUCLEONS
NUCLEOTIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
PHOSPHORUS-GROUP TRANSFERASES
PHOSPHOTRANSFERASES
PROTEINS
PROTONS
RECEPTORS
SPECTRA
TIME DEPENDENCE
TRANSFERASES
TRANSITION ELEMENT COMPOUNDS