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Titolo:
Coagulation factor IXa: the relaxed conformation of Tyr99 blocks substratebinding
Autore:
Hopfner, KP; Lang, A; Karcher, A; Sichler, K; Kopetzki, E; Brandstetter, H; Huber, R; Bode, W; Engh, RA;
Indirizzi:
Max Planck Inst Biochem, Abt Strukturforsch, D-82152 Martinsried, Germany Max Planck Inst Biochem Martinsried Germany D-82152 Martinsried, Germany Roche Diagnost AG, Pharmaceut Res, D-82372 Penzberg, Germany Roche Diagnost AG Penzberg Germany D-82372 es, D-82372 Penzberg, Germany
Titolo Testata:
STRUCTURE WITH FOLDING & DESIGN
fascicolo: 8, volume: 7, anno: 1999,
pagine: 989 - 996
SICI:
0969-2126(19990815)7:8<989:CFITRC>2.0.ZU;2-U
Fonte:
ISI
Lingua:
ENG
Soggetto:
RAY CRYSTAL-STRUCTURE; BOVINE FACTOR-IX; X STUART FACTOR; BLOOD-COAGULATION; ACTIVE-SITE; FACTOR-VIIIA; FACTOR-XIA; SERINE PROTEASES; CATALYTIC DOMAIN; CHRISTMAS FACTOR;
Keywords:
crystal structure; drug design; recombinant proteins; substrate-binding sites;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
42
Recensione:
Indirizzi per estratti:
Indirizzo: Engh, RA Max Planck Inst Biochem, Abt Strukturforsch, D-82152 Martinsried,Germany Max Planck Inst Biochem Martinsried Germany D-82152 ed, Germany
Citazione:
K.P. Hopfner et al., "Coagulation factor IXa: the relaxed conformation of Tyr99 blocks substratebinding", STRUCT F D, 7(8), 1999, pp. 989-996

Abstract

Background: Among the S1 family of serine proteinases, the blood coagulation factor lXa (flXa) is uniquely inefficient against synthetic peptide substrates. Mutagenesis studies show that a loop of residues at the S2-S4 substrate-binding cleft (the 99-loop) contributes to the low efficiency. The crystal structure of porcine flXa in complex with the inhibitor D-Phe-Pro-Arg-chloromethylketone (PPACK) was unable to directly clarify the role of the 99-loop, as the doubly covalent inhibitor induced an active conformation of flXa. Results: The crystal structure of a recombinant two-domain construct of human flXa in complex with rho-aminobenzamidine shows that the Tyr99 sidechain adopts an atypical conformation in the absence of substrate interactions. In this conformation, the hydroxyl group occupies the volume correspondingto the mainchain of a canonically bound substrate P2 residue. To accommodate substrate binding, Tyr99 must adopt a higher energy conformation that creates the S2 pocket and restricts the S4 pocket, as in flXa-PPACK. The energy cost may contribute significantly to the poor K-M values of flXa for chromogenic substrates. In homologs, such as factor Xa and tissue plasminogen activator, the different conformation of the 99-loop leaves Tyr99 in low-energy conformations in both bound and unbound states. Conclusions: Molecular recognition of substrates by flXa seems to be determined by the action of the 99-loop on Tyr99. This is in contrast to other coagulation enzymes where, in general, the chemical nature of residue 99 determines molecular recognition in S2 and S3-S4. This dominant role on substrate interaction suggests that the 99-loop may be rearranged in the physiological fX activation complex of flXa, fVilla, and fX.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 18/09/20 alle ore 16:53:04