1HUC

THE REFINED 2.15 ANGSTROMS X-RAY CRYSTAL STRUCTURE OF HUMAN LIVER CATHEPSIN B: THE STRUCTURAL BASIS FOR ITS SPECIFICITY

DOI: 10.2210/pdb1HUC/pdb

Classification: THIOL PROTEASE
Organism(s): Homo sapiens
Mutation(s): No

Deposited: 1993-04-21 Released: 1995-01-26
Deposition Author(s): Musil, D., Bode, W.

Experimental Data Snapshot

Method: X-RAY DIFFRACTION
Resolution: 2.10 Å
R-Value Observed: 0.164

wwPDB Validation 3D Report Full Report

This is version 1.2 of the entry. See complete history.

Literature

The refined 2.15 A X-ray crystal structure of human liver cathepsin B: the structural basis for its specificity.

Musil, D., Zucic, D., Turk, D., Engh, R.A., Mayr, I., Huber, R., Popovic, T., Turk, V., Towatari, T., Katunuma, N., Bode, W.

(1991) EMBO J 10: 2321-2330

PubMed: 1868826 Search on PubMedSearch on PubMed Central
Primary Citation of Related Structures:
1HUC

PubMed Abstract:

From the lysosomal cysteine proteinase cathepsin B, isolated from human liver in its two-chain form, monoclinic crystals were obtained which contain two molecules per asymmetric unit. The molecular structure was solved by a combination of Patterson search and heavy atom replacement methods (simultaneously with rat cathepsin B) and refined to a crystallographic R value of 0.164 using X-ray data to 2.15 A resolution. The overall folding pattern of cathepsin B and the arrangement of the active site residues are similar to the related cysteine proteinases papain, actinidin and calotropin DI. 166 alpha-carbon atoms out of 248 defined cathepsin B residues are topologically equivalent (with an r.m.s. deviation of 1.04 A) with alpha-carbon atoms of papain. However, several large insertion loops are accommodated on the molecular surface and modify its properties. The disulphide connectivities recently determined for bovine cathepsin B by chemical means were shown to be correct. Some of the primed subsites are occluded by a novel insertion loop, which seems to favour binding of peptide substrates with two residues carboxy-terminal to the scissile peptide bond; two histidine residues (His110 and His111) in this "occluding loop' provide positively charged anchors for the C-terminal carboxylate group of such polypeptide substrates. These structural features explain the well-known dipeptidyl carboxypeptidase activity of cathepsin B. The other subsites adjacent to the reactive site Cys29 are relatively similar to papain; Glu245 in the S2 subsite favours basic P2-side chains. The above mentioned histidine residues, but also the buried Glu171 might represent the group with a pKa of approximately 5.5 near the active site, which governs endo- and exopeptidase activity. The "occluding loop' does not allow cystatin-like protein inhibitors to bind to cathepsin B as they do to papain, consistent with the reduced affinity of these protein inhibitors for cathepsin B compared with the related plant enzymes.

Organizational Affiliation:

Max-Planck-Institut für Biochemie, Martinsried, FRG.

Macromolecules

Find similar proteins by:

(by identity cutoff) | Structure

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
CATHEPSIN B	A, C	47	Homo sapiens	Mutation(s): 0 Gene Names: CTSB, CPSB EC: 3.4.22.1
UniProt & NIH Common Fund Data Resources
Find proteins for P07858 (Homo sapiens) Explore P07858 Go to UniProtKB: P07858
PHAROS: P07858 GTEx: ENSG00000164733
Protein Feature View Expand
Reference Sequence

Find similar proteins by:

(by identity cutoff) | Structure

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details	Image
CATHEPSIN B	B, D	205	Homo sapiens	Mutation(s): 0 Gene Names: CTSB, CPSB EC: 3.4.22.1
UniProt & NIH Common Fund Data Resources
Find proteins for P07858 (Homo sapiens) Explore P07858 Go to UniProtKB: P07858
PHAROS: P07858 GTEx: ENSG00000164733
Protein Feature View Expand
Reference Sequence