title: A snapshot of enzyme catalysis using electrospray ionization mass spectrometry.
abstract: Insights into the early molecular events involving protein-ligand/substrate interactions such as protein signaling and enzyme catalysis can be obtained by examining these processes on a very short, millisecond time scale. We have used time-resolved electrospray mass spectrometry to delineate the catalytic mechanism of a key enzyme in bacterial lipopolysaccharide biosynthesis, 3-deoxy-d-manno-2-octulosonate-8-phosphate synthase (KDO8PS). Direct real-time monitoring of the catalytic reaction under single enzyme turnover conditions reveals a novel hemiketal phosphate intermediate bound to the enzyme in a noncovalent complex that establishes the reaction pathway. This study illustrates the successful application of mass spectrometry to reveal transient biochemical processes and opens a new time domain that can provide detailed structural information of short-lived protein-ligand complexes.
authors.affiliation: Department of Pharmacology, Yale University School of Medicine, New Haven, CT, USA.
authors.forename: Zhili
authors.initials: Z
authors.lastname: Li
authors.forename: Apurba K
authors.initials: AK
authors.lastname: Sau
authors.forename: Shida
authors.initials: S
authors.lastname: Shen
authors.forename: Craig
authors.initials: C
authors.lastname: Whitehouse
authors.forename: Timor
authors.initials: T
authors.lastname: Baasov
authors.forename: Karen S
authors.initials: KS
authors.lastname: Anderson
mesh_terms: D000446:Aldehyde-Lyases / Q000737:chemistry* / Q000378:metabolism*; D002384:Catalysis; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: C020011:2-dehydro-3-deoxyphosphooctonate aldolase; D000446:Aldehyde-Lyases