PDBsum entry 2cb5

Hydrolase

PDB id: 2cb5

Contents

Protein chain

453 a.a. *

Waters ×564

* Residue conservation analysis

PDB id:

2cb5

Name:

Hydrolase

Title:

Human bleomycin hydrolase, c73s/dele455 mutant

Structure:

Protein (bleomycin hydrolase). Chain: a, b. Engineered: yes. Mutation: yes

Source:

Homo sapiens. Human. Organism_taxid: 9606. Cellular_location: cytoplasm. Expressed in: escherichia coli. Expression_system_taxid: 562.

Biol. unit:

Hexamer (from PQS)

Resolution:

1.85Å R-factor: 0.182 R-free: 0.210

Authors:

P.A.O'Farrell,F.Gonzalez,W.Zheng,S.A.Johnston,L.Joshua-Tor

Key ref:

P.A.O'Farrell et al. (1999). Crystal structure of human bleomycin hydrolase, a self-compartmentalizing cysteine protease. Structure, 7, 619-627. PubMed id: 10404591 DOI: 10.1016/S0969-2126(99)80083-5

Date:

02-Mar-99 Release date: 06-Mar-00

Protein chains

Q13867  (BLMH_HUMAN) -  Bleomycin hydrolase from Homo sapiens

Seq: 455 a.a.

Struc: 453 a.a.*

* PDB and UniProt seqs differ at 3 residue positions (black crosses)

Enzyme reactions

• Enzyme class: E.C.3.4.22.40 - bleomycin hydrolase.
• Reaction: Inactivates bleomycin B2 (a cytotoxic glycometallopeptide) by hydrolysis of a carboxyamide bond of b-aminoalanine, but also shows general aminopeptidase activity. The specificity varies somewhat with source, but amino acid arylamides of Met, Leu and Ala are preferred.

DOI no: 10.1016/S0969-2126(99)80083-5

Structure 7:619-627 (1999)

PubMed id: 10404591

Crystal structure of human bleomycin hydrolase, a self-compartmentalizing cysteine protease.

P.A.O'Farrell, F.Gonzalez, W.Zheng, S.A.Johnston, L.Joshua-Tor.

ABSTRACT

BACKGROUND: Bleomycin hydrolase (BH) is a cysteine protease that is found in all tissues in mammals as well as in many other eukaryotes and prokaryotes. Although its conserved cellular function is as yet unknown, human bleomycin hydrolase (hBH) has clinical significance in that it is thought to be the major cause of tumor cell resistance to bleomycin chemotherapy. In addition, it has been reported that an allelic variant of hBH is genetically linked to Alzheimer's disease. RESULTS: We have determined the crystal structures of wild-type hBH and of a mutant form of the enzyme. The overall structure is very similar to that of the previously determined yeast homolog, however, there is a striking difference in the charge distribution. The central channel, which has a strong positive electrostatic potential in the yeast protein, is slightly negative in hBH. We have determined that hBH does not have the DNA-binding activity of the yeast protein and that the enzyme is localized to the cytoplasm. CONCLUSIONS: The difference in charge distribution between the yeast and human BH enzymes is most likely responsible for the difference in DNA-binding activity. Nevertheless, the C-terminal autoprocessing activity and the role of the C terminus as a determinant for peptidase activity are conserved between the yeast and human forms. The structure of hBH suggests that the putative Alzheimer's disease linked variation does not directly alter the intrinsic peptidase activity. Rather, the position of the mutation suggests that it could affect interactions with another protein, which may modulate peptidase activity through repositioning of the C terminus.

Selected figure(s)

Figure 3.
Figure 3. The C terminus of hBH. Residues 447–454 of the wild-type protein, as well as the catalytic Cys73, are shown as bonds colored according to atom type. The corresponding residues of the Cys73→Ser/ΔGlu455 mutant protein are shown in cyan. The sidechains of the catalytic residues His372 and Asp396 are shown with yellow bonds, as is the sidechain of Gln67, which stabilizes the oxyanion intermediate during catalysis. Hydrogen-bond interactions of the mutant protein – between the C-terminal alanine and the sidechain of Gln67 and the amide nitrogen atoms of Ser73 and Trp74, and between Ser73 and the backbone amide of residue 373 – are shown as dotted white lines. Arrows indicate the Cα atoms of labeled residues. Gly451 is the elbow at which the C-terminal arm rotates and extends.

The above figure is reprinted by permission from Cell Press: Structure (1999, 7, 619-627) copyright 1999.

Figure was selected by an automated process.