A Phosphoenzyme Mimic, Overlapping Catalytic Sites and Reaction Coordinate Motion for Human NAMPT
Nicotinamide phosphoribosyltransferase (NAMPT) is highly evolved to capture nicotinamide (NAM) and replenish the nicotinamide adenine dinucleotide (NAD+) pool during ADP-ribosylation and transferase reactions. ATP-phosphorylation of an active-site histidine causes catalytic activation, increasing NAM affinity by 160,000. Crystal structures of NAMPT with catalytic site ligands identify the phosphorylation site, establish its role in catalysis, demonstrate unique overlapping ATP and phosphoribosyltransferase sites, and establish reaction coordinate motion. NAMPT structures with beryllium fluoride indicate a covalent H247-BeF3- as the phosphohistidine mimic. Activation of NAMPT by H247-phosphorylation causes stabilization of the enzyme-phosphoribosylpyrophosphate complex, permitting efficient capture of NAM. Reactant and product structures establish reaction coordinate motion for NAMPT to be migration of the ribosyl anomeric carbon from the pyrophosphate leaving group to the nicotinamide-N1 while the 5-phosphoryl group, the pyrophosphate moiety, and the nicotinamide ring remain fixed in the catalytic site.
- Research Organization:
- Brookhaven National Laboratory (BNL) National Synchrotron Light Source
- Sponsoring Organization:
- Doe - Office Of Science
- DOE Contract Number:
- AC02-98CH10886
- OSTI ID:
- 979985
- Report Number(s):
- BNL--92903-2010-JA
- Journal Information:
- Proceedings of the National Academy of Sciences of the United States of America, Journal Name: Proceedings of the National Academy of Sciences of the United States of America Journal Issue: 33 Vol. 106
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
99 GENERAL AND MISCELLANEOUS
AFFINITY
ATP
BERYLLIUM FLUORIDES
CAPTURE
CARBON
CATALYSIS
COORDINATES
CRYSTAL STRUCTURE
HISTIDINE
HUMAN POPULATIONS
LIGANDS
MIGRATION
MOTION
NAD
NICOTINAMIDE
PHOSPHORYLATION
PONDS
PROGRAMMING LANGUAGES
PYROPHOSPHATES
RINGS
STABILIZATION
TRANSFERASES
national synchrotron light source