PDBsum entry 1ylc

Hydrolase/inhibitor

PDB id

1ylc

Contents

			Protein chains

					223 a.a.


					56 a.a.

			Ligands

					SO4 ×2

			Metals

					_CA

			Waters ×227

References listed in PDB file

Key reference

Title

Partially folded bovine pancreatic trypsin inhibitor analogues attain fully native structures when co-Crystallized with s195a rat trypsin.

Authors

I.V.Getun, C.K.Brown, J.Tulla-Puche, D.Ohlendorf, C.Woodward, G.Barany.

Ref.

J Mol Biol, 2008, 375, 812-823. [DOI no: 10.1016/j.jmb.2007.10.084]

PubMed id

18054043

Abstract

Crystal structures, at 1.7 A resolution, were solved for complexes between each of two chemically synthesized partially folded analogues of bovine pancreatic trypsin inhibitor (BPTI) with the proteolytically inactive rat trypsin mutant S195A. The BPTI analogue termed [14-38](Abu) retains only the disulfide bond between Cys14 and Cys38, while Cys5, Cys30, Cys51, and Cys55 are replaced by isosteric alpha-amino-n-butyric acid residues. The analogue K26P,A27D[14-38](Abu) contains two further replacements, by statistically favored residues, in the type I beta-turn that has been suggested to be a main site for initiation of BPTI folding. As a control, the structure of the complex between S195A trypsin and wild-type BPTI was also solved. Despite significant differences in the degree of structure detected among these three BPTIs in solution by several biophysical techniques, their tertiary folds once bound to S195A trypsin in a crystalline lattice are essentially superimposable.



	Figure 4. Fig. 4. Positions of BPTI internal waters 500, 512, 522, 525, and 529 in the complexes of S195A trypsin with wild-type BPTI (cyan), with [14–38][Abu] (blue), and with K26P,A27D[14–38][Abu] (magenta).		Figure 5. Fig. 5. 2F[o] − F[c] density in the S195A trypsin–wild-type BPTI complex around the 30–51 disulfide (pink) and corresponding 2F[o] − F[c] density in the S195A trypsin–K26P,A27D[14–38][Abu] complex around the paired Abu residues (white).

PROCHECK

	Headers