6AXW

Structure of the I124A mutant of the HIV-1 capsid protein


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.236 
  • R-Value Work: 0.189 
  • R-Value Observed: 0.193 

wwPDB Validation   3D Report Full Report


This is version 1.6 of the entry. See complete history


Literature

Identification of a Structural Element in HIV-1 Gag Required for Virus Particle Assembly and Maturation.

Novikova, M.Adams, L.J.Fontana, J.Gres, A.T.Balasubramaniam, M.Winkler, D.C.Kudchodkar, S.B.Soheilian, F.Sarafianos, S.G.Steven, A.C.Freed, E.O.

(2018) mBio 9

  • DOI: https://doi.org/10.1128/mBio.01567-18
  • Primary Citation of Related Structures:  
    6AXR, 6AXW

  • PubMed Abstract: 

    Late in the HIV-1 replication cycle, the viral structural protein Gag is targeted to virus assembly sites at the plasma membrane of infected cells. The capsid (CA) domain of Gag plays a critical role in the formation of the hexameric Gag lattice in the immature virion, and, during particle release, CA is cleaved from the Gag precursor by the viral protease and forms the conical core of the mature virion. A highly conserved Pro-Pro-Ile-Pro (PPIP) motif (CA residues 122 to 125) [PPIP(122-125)] in a loop connecting CA helices 6 and 7 resides at a 3-fold axis formed by neighboring hexamers in the immature Gag lattice. In this study, we characterized the role of this PPIP(122-125) loop in HIV-1 assembly and maturation. While mutations P123A and P125A were relatively well tolerated, mutation of P122 and I124 significantly impaired virus release, caused Gag processing defects, and abolished infectivity. X-ray crystallography indicated that the P122A and I124A mutations induce subtle changes in the structure of the mature CA lattice which were permissive for in vitro assembly of CA tubes. Transmission electron microscopy and cryo-electron tomography demonstrated that the P122A and I124A mutations induce severe structural defects in the immature Gag lattice and abrogate conical core formation. Propagation of the P122A and I124A mutants in T-cell lines led to the selection of compensatory mutations within CA. Our findings demonstrate that the CA PPIP(122-125) loop comprises a structural element critical for the formation of the immature Gag lattice. IMPORTANCE Capsid (CA) plays multiple roles in the HIV-1 replication cycle. CA-CA domain interactions are responsible for multimerization of the Gag polyprotein at virus assembly sites, and in the mature virion, CA monomers assemble into a conical core that encapsidates the viral RNA genome. Multiple CA regions that contribute to the assembly and release of HIV-1 particles have been mapped and investigated. Here, we identified and characterized a Pro-rich loop in CA that is important for the formation of the immature Gag lattice. Changes in this region disrupt viral production and abrogate the formation of infectious, mature virions. Propagation of the mutants in culture led to the selection of second-site compensatory mutations within CA. These results expand our knowledge of the assembly and maturation steps in the viral replication cycle and may be relevant for development of antiviral drugs targeting CA.


  • Organizational Affiliation

    Virus-Cell Interaction Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
HIV-1 capsid protein230Human immunodeficiency virus 1Mutation(s): 1 
Gene Names: gag
UniProt
Find proteins for P12493 (Human immunodeficiency virus type 1 group M subtype B (isolate NY5))
Explore P12493 
Go to UniProtKB:  P12493
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP12493
Sequence Annotations
Expand
  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
IOD
Query on IOD

Download Ideal Coordinates CCD File 
B [auth A]
C [auth A]
D [auth A]
E [auth A]
F [auth A]
B [auth A],
C [auth A],
D [auth A],
E [auth A],
F [auth A],
G [auth A],
H [auth A],
I [auth A],
J [auth A]
IODIDE ION
I
XMBWDFGMSWQBCA-UHFFFAOYSA-M
CL
Query on CL

Download Ideal Coordinates CCD File 
K [auth A]
L [auth A]
M [auth A]
N [auth A]
O [auth A]
K [auth A],
L [auth A],
M [auth A],
N [auth A],
O [auth A],
P [auth A],
Q [auth A],
R [auth A],
S [auth A],
T [auth A]
CHLORIDE ION
Cl
VEXZGXHMUGYJMC-UHFFFAOYSA-M
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.236 
  • R-Value Work: 0.189 
  • R-Value Observed: 0.193 
  • Space Group: P 6
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 92.611α = 90
b = 92.611β = 90
c = 57.954γ = 120
Software Package:
Software NamePurpose
Aimlessdata scaling
Blu-Icedata collection
REFMACrefinement
PDB_EXTRACTdata extraction
Aimlessdata reduction
PHASERphasing

Structure Validation

View Full Validation Report



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute Of Allergy and Infectious Diseases (NIH/NIAID)United StatesAI120860

Revision History  (Full details and data files)

  • Version 1.0: 2018-09-12
    Type: Initial release
  • Version 1.1: 2018-10-24
    Changes: Data collection, Database references
  • Version 1.2: 2018-10-31
    Changes: Data collection, Database references
  • Version 1.3: 2018-11-14
    Changes: Data collection, Database references
  • Version 1.4: 2019-02-20
    Changes: Author supporting evidence, Data collection
  • Version 1.5: 2019-12-11
    Changes: Author supporting evidence
  • Version 1.6: 2023-10-04
    Changes: Data collection, Database references, Refinement description