Crystal structures of. alpha. -lytic protease complexes with irreversibly bound phosphonate esters

Journal Article · Tue Feb 26 00:00:00 EST 1991 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00222a032· OSTI ID:5621063

Bone, R; Agard, D A ^[1]; Sampson, N S; Barlett, P A ^[2]

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1. Univ. of California, San Francisco (United States)
2. Univ. of California, Berkeley (United States)

The structures of the complexes with {alpha}-lytic protease of both phosphorus stereoisomers of N-((2S)-2-((((1R)-1-(N-((tert-butyloxycarbonyl)-L-alanyl-L-alanyl-L-prolyl)amino)-2-methylpropyl)-phenoxyphosphinyl)oxy)propanoyl)-L-alanine methyl ester, an analogue of the peptide Boc-Ala-Ala-Pro-Val-Ala-Ala where Val is replaced with an analogous phosphonate phenyl ester and the subsequent Ala is replaced with lactate, have been determined to high resolution (1.9 {angstrom}) by X-ray crystallography. Both stereoisomers inactivate the enzyme but differ by factor of 2 in the second-order rate constant for inactivation. One isomer (B) forms a tetrahedral adduct in which the phosphonate phenyl ester is displaced by the active site serine (S195) and interacts with the enzyme across seven substrate recognition sites that span both sides of the scissile bond. The other isomer (A) forms a mixture of two different tetrahedral adducts in the active site, both covalently bonded to Ser 195. One adduct, at approximately 58% occupancy, is exactly the same in structure as the complex formed with isomer B, and the other adduct, at 42% occupancy, has lost the two residues C-terminal to the scissile bond by hydrolysis. As very little change in structure accompanies the histidine rotation, the complex with isomer B provides an excellent mimic for the structure of the transition state (or high-energy reaction intermediate) that spans both sides of the scissile bond.

• OSTI ID: 5621063
• Journal Information: Biochemistry; (United States), Vol. 30:8; ISSN 0006-2960
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
PEPTIDE HYDROLASES
X-RAY DIFFRACTION
CRYSTAL STRUCTURE
ELECTRON DENSITY
HISTIDINE
ISOMERS
MOLECULAR STRUCTURE
PHOSPHONIC ACID ESTERS
AMINO ACIDS
AZOLES
CARBOXYLIC ACIDS
COHERENT SCATTERING
DIFFRACTION
ENZYMES
ESTERS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HYDROLASES
IMIDAZOLES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
PROTEINS
SCATTERING
550602* - Medicine- External Radiation in Diagnostics- (1980-)