Crystallization, data collection and processing of the chymotrypsin-BTCI-trypsin ternary complex.
A ternary complex of the black-eyed pea trypsin and chymotrypsin inhibitor (BTCI) with trypsin and chymotrypsin was crystallized by the sitting-drop vapour-diffusion method with 0.1 M HEPES pH 7.5, 10%(w/v) polyethylene glycol 6000 and 5%(v/v) 2-methyl-2,4-pentanediol as precipitant. BTCI is a small protein with 83 amino-acid residues isolated from Vigna unguiculata seeds and is able to inhibit trypsin and chymotrypsin simultaneously by forming a stable ternary complex. X-ray data were collected from a single crystal of the trypsin-BTCI-chymotrypsin ternary complex to 2.7 A resolution under cryogenic conditions. The structure of the ternary complex was solved by molecular replacement using the crystal structures of the BTCI-trypsin binary complex (PDB code 2g81) and chymotrypsin (PDB code 4cha) as search models.
Esteves
Gisele Ferreira
GF
Laboratório de Biofísica, Instituto de Ciências Biológicas, Universidade de Brasília, 70910-900 Brasília-DF, Brazil.
Teles
Rozeni Chagas Lima
RC
Cavalcante
Nayara Silva
NS
Neves
David
D
Ventura
Manuel Mateus
MM
Barbosa
João Alexandre Ribeiro Gonçalves
JA
de Freitas
Sonia Maria
SM
D000818:Animals; D002417:Cattle; D002850:Chromatography, Gel; D002918:Chymotrypsin / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D003460:Crystallization; D018532:Pisum sativum / Q000201:enzymology*; D011480:Protease Inhibitors / Q000737:chemistry* / Q000302:isolation & purification; D011485:Protein Binding; D020836:Protein Structure, Quaternary; D014357:Trypsin / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*
D011480:Protease Inhibitors; D002918:Chymotrypsin; D014357:Trypsin