1DIF

HIV-1 PROTEASE IN COMPLEX WITH A DIFLUOROKETONE CONTAINING INHIBITOR A79285


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.70 Å
  • R-Value Work: 0.198 
  • R-Value Observed: 0.198 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Inhibition and catalytic mechanism of HIV-1 aspartic protease.

Silva, A.M.Cachau, R.E.Sham, H.L.Erickson, J.W.

(1996) J Mol Biol 255: 321-346

  • DOI: 10.1006/jmbi.1996.0026
  • Primary Citation of Related Structures:  
    1DIF

  • PubMed Abstract: 
  • The structure of the HIV-1 protease in complex with a pseudo-C2 symmetric inhibitor, which contains a central difluoroketone motif, has been determined with X-ray diffraction data extending to 1.7 A resolution. The electron density map clearly indica ...

    The structure of the HIV-1 protease in complex with a pseudo-C2 symmetric inhibitor, which contains a central difluoroketone motif, has been determined with X-ray diffraction data extending to 1.7 A resolution. The electron density map clearly indicates that the inhibitor is bound in a symmetric fashion as the hydrated, or gemdiol, form of the difluoroketone. Refinement of the complex reveals a unique, and almost symmetric, set of interactions between the geminal hydroxyl groups, the geminal fluorine atoms, and the active-site aspartate residues. Several hydrogen bonding patterns are consistent with that conformation. The lowest energy hydrogen disposition, as determined by semiempirical energy calculations, shows only one active site aspartate protonated. A comparison between the corresponding dihedral angles of the difluorodiol core and those of a hydrated peptide bond analog, calculated ab-initio, shows that the inhibitor core is a mimic of a hydrated peptide bond in a gauche conformation. The feasibility of an anti-gauche transition for a peptide bond after hydration is verified by extensive molecular dynamics simulations. The simulations suggest that rotation about the C-N scissile bond would readily occur after hydration and would be driven by the optimization of the interactions of peptide side-chains with the enzyme. These results, together with the characterization of a transition state leading to bond breakage via a concerted exchange of two protons, suggest a proteolysis mechanism whereby only one active site aspartate is initially protonated. The steps of this mechanism are: asymmetric binding of the substrate; hydration of the peptidic carbonyl by an active site water; proton translocation between the active site aspartate residues simultaneously with carbonyl hydration; optimization of the binding of the entire substrate facilitated by the flexible structure of the hydrated peptide bond, which, in turn, forces the hydrated peptide bond to assume a gauche conformation; simultaneous proton exchange whereby one hydroxyl donates a proton to the charged aspartate, and, at the same time, the nitrogen lone pair accepts a proton from the other aspartate; and, bond breakage and regeneration of the initial protonation state of the aspartate residues.


    Organizational Affiliation

    Structural Biochemistry Program, National Cancer Institute, Frederick, MD 21702, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
HIV-1 PROTEASEAB99Human immunodeficiency virus 1Mutation(s): 0 
EC: 3.4.23.16 (UniProt), 2.7.7.49 (UniProt), 2.7.7.7 (UniProt), 3.1.26.13 (UniProt), 3.1.13.2 (UniProt), 2.7.7 (UniProt), 3.1 (UniProt)
Find proteins for P03367 (Human immunodeficiency virus type 1 group M subtype B (isolate BRU/LAI))
Explore P03367 
Go to UniProtKB:  P03367
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
A85
Query on A85

Download CCD File 
B
N-{1-BENZYL-2,2-DIFLUORO-3,3-DIHYDROXY-4-[3-METHYL-2-(3-METHYL-3-PYRIDIN-2-YLMETHYL-UREIDO)-BUTYRYLAMINO]-5-PHENYL-PENTYL}-3-METHYL-2-(3-METHYL-3-PYRIDIN-2-YLMETHYL-UREIDO)-BUTYRAMIDE
C44 H56 F2 N8 O6
CGJKKYBHEOTRNM-ZQWQDMLBSA-N
 Ligand Interaction
BME
Query on BME

Download CCD File 
A, B
BETA-MERCAPTOETHANOL
C2 H6 O S
DGVVWUTYPXICAM-UHFFFAOYSA-N
 Ligand Interaction
External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
A85Ki:  0.02200000174343586   nM  Binding MOAD
A85Ki :  0.02200000174343586   nM  PDBBind
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.70 Å
  • R-Value Work: 0.198 
  • R-Value Observed: 0.198 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 52α = 90
b = 59.9β = 90
c = 62.1γ = 90
Software Package:
Software NamePurpose
X-PLORmodel building
X-PLORrefinement
MOSFLMdata reduction
X-PLORphasing

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1996-03-08
    Type: Initial release
  • Version 1.1: 2008-03-03
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance