PDBsum entry 1a8k

Hydrolase/hydrolase inhibitor

PDB id: 1a8k

Contents

Protein chains

99 a.a. *

Ligands

0Q4 ×2

Waters ×477

* Residue conservation analysis

PDB id:

1a8k

Name:

Hydrolase/hydrolase inhibitor

Title:

Crystallographic analysis of human immunodeficiency virus 1 protease with an analog of the conserved ca-p2 substrate: interactions with frequently occurring glutamic acid residue at p2' position of substrates

Structure:

HIV protease. Chain: a, b, d, e. Engineered: yes. Mutation: yes

Source:

Human immunodeficiency virus 1. Organism_taxid: 11676. Expressed in: escherichia coli. Expression_system_taxid: 562

Biol. unit:

Homo-Dimer (from PDB file)

Resolution:

2.00Å R-factor: 0.174 R-free: 0.319

Authors:

I.T.Weber,J.Wu,J.Adomat,R.W.Harrison,A.R.Kimmel,E.M.Wondrak,J.M.Louis

Key ref:

I.T.Weber et al. (1997). Crystallographic analysis of human immunodeficiency virus 1 protease with an analog of the conserved CA-p2 substrate -- interactions with frequently occurring glutamic acid residue at P2' position of substrates. Eur J Biochem, 249, 523-530. PubMed id: 9370363

Date:

27-Mar-98 Release date: 13-Jan-99

Protein chains

P03367  (POL_HV1BR) -  Gag-Pol polyprotein from Human immunodeficiency virus type 1 group M subtype B (isolate BRU/LAI)

Seq: 1447 a.a.

Struc: 99 a.a.*

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

Enzyme reactions

• Enzyme class 1: E.C.2.7.7.- - ?????
• Enzyme class 2: E.C.2.7.7.49 - RNA-directed Dna polymerase.
• Reaction: DNA(n) + a 2'-deoxyribonucleoside 5'-triphosphate = DNA(n+1) + diphosphate
• Enzyme class 3: E.C.2.7.7.7 - DNA-directed Dna polymerase.
• Reaction: DNA(n) + a 2'-deoxyribonucleoside 5'-triphosphate = DNA(n+1) + diphosphate
• Enzyme class 4: E.C.3.1.-.-
• Enzyme class 5: E.C.3.1.13.2 - exoribonuclease H.
• Reaction: Exonucleolytic cleavage to 5'-phosphomonoester oligonucleotides in both 5'- to 3'- and 3'- to 5'-directions.
• Enzyme class 6: E.C.3.1.26.13 - retroviral ribonuclease H.
• Enzyme class 7: E.C.3.4.23.16 - HIV-1 retropepsin.
• Reaction: Specific for a P1 residue that is hydrophobic, and P1' variable, but often Pro.

Note, where more than one E.C. class is given (as above), each may correspond to a different protein domain or, in the case of polyprotein precursors, to a different mature protein.

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

reference

Eur J Biochem 249:523-530 (1997)

PubMed id: 9370363

Crystallographic analysis of human immunodeficiency virus 1 protease with an analog of the conserved CA-p2 substrate -- interactions with frequently occurring glutamic acid residue at P2' position of substrates.

I.T.Weber, J.Wu, J.Adomat, R.W.Harrison, A.R.Kimmel, E.M.Wondrak, J.M.Louis.

ABSTRACT

Human immunodeficiency virus type 1 (HIV-1) protease hydrolysis of the Gag CA-p2 cleavage site is crucial for virion maturation and is optimal at acidic pH. To understand the processing of the CA-p2 site, we have determined the structure of HIV-1 protease complexed with an analog of the CA-p2 site, the reduced peptide inhibitor Arg-Val-Leu-r-Phe-Glu-Ala-Ahx-NH2 [r denotes the reduced peptide bond and Ahx 2-aminohexanoic acid (norleucine), respectively]. The crystal structure was refined to an R-factor of 0.17 at 0.21-nm resolution. The crystals have nearly the same lattice as related complexes in P2(1)2(1)2(1) which have twofold disordered inhibitor, but are in space group P2(1). and the asymmetric unit contains two dimers of HIV-1 protease related by 180 degrees rotation. An approximate non-crystallographic symmetry has replaced the exact crystal symmetry resulting in well-ordered inhibitor structure. Each protease dimer binds one ordered inhibitor molecule, but in opposite orientations. The interactions of the inhibitor with the two dimers are very similar for the central P2 Val to P2' Glu residues, but show more variation for the distal P3 Arg and P4' Ahx residues. Importantly, the carboxylate oxygens of Glu at P2' in the inhibitor are within hydrogen-bonding distance of a carboxylate oxygen of Asp30 of the protease suggesting that the two side chains share a proton. This interaction suggests that the enzyme-substrate complex is additionally stabilized at lower pH. The importance of this interaction is emphasized by the absence of polymorphisms of Asp30 in the protease and variants of P2' Glu in the critical CA-p2 cleavage site.