CA - P24, Core Antigen capsid protein

HIV CA forms the conical core of the viral particle.




Homology model of CA made using 1E6J as a reference structure - created by Ryan Doherty using SwissModel, SwissPDB Viewer and POV-Ray
[animated gif: 320x240 ]
ViralZone:HIV-1
PDB: 1E6J (HIV-1 CA)
SwissProt: P04591 (HIV-1 HXB2 GAG)
Chime Tutorial: not available
Los Alamos HIV structure DB: Core Antigen Capsid
EMBL: K03455 [EMBL/GenBank/DDBJ]
BioAfrica: Gag Protein Data Mining Tool


Isoforms:

  • p24 (231 amino acids)

Cleavage site:


Localization:

  • Virion
  • Cell Cytoplasm

Function:

  • Forms the conical core of the viral particle that encapsulates the genomic RNA-nucleocapsid complex (Ref. # 7)


Additional Information:

  • CA is phosphorylated
  • CA interacts with Cyclophilin A, leading to its incorporation into the virion (Ref. #4 & #5)
  • disruption of the CA/Cyclophilin A interaction leads to inhibition of viral replication (Ref. #6)

Genomic Location: [TOP]

Reference Sequences:

HIV-1 (HXB2):

          10         20         30         40         50         60         70 
| | | | | | |
PIVQNIQGQM VHQAISPRTL NAWVKVVEEK AFSPEVIPMF SALSEGATPQ DLNTMLNTVG GHQAAMQMLK
80 90 100 110 120 130 140
| | | | | | |
ETINEEAAEW DRVHPVHAGP IAPGQMREPR GSDIAGTTST LQEQIGWMTN NPPIPVGEIY KRWIILGLNK
150 160 170 180 190 200 210
| | | | | | |
IVRMYSPTSI LDIRQGPKEP FRDYVDRFYK TLRAEQASQE VKNWMTETLL VQNANPDCKT ILKALGPAAT
220 230
| |
LEEMMTACQG VGGPGHKARV L

[download in fasta format]

Length: 231 amino acids
Molecular Weight: 25579 Da
Theoretical pI: 6.26

Protein Domains/Folds/Motifs: [TOP]

InterPro signature for Retrovirus capsid, C-terminal - IPR008916


InterPro signature for Retrovirus capsid, N-terminal core - IPR008919



Secondary Structure prediction:

Antigenic Sites - EMBOSS:



Predicted Motifs: Printer-friendly version

N-glycosylation:
N-myristoylation:
Amidation:
Protein kinase C:
Casein kinase II:
Tyrosine kinase:
cAMP / cGMP kinase:
Cell attachment motif:
Asp Protease motif:
Asp Prot Retro motif:
Cysteine-rich Region:
Tryptophan-rich Region:
Zinc-finger CCHC motif:
Leucine Zipper motif:

Protein-Protein Interactions: [TOP]

  • CA interacts with Cyclophilin A, which acts during the disassembly of the viral core after infecting a new cell (Ref. #6)


Primary and Secondary Database Entries: [TOP]

Identifiers:

ViralZone: HIV-1
PDB/MMDB: Search for HIV-1 & Capsid

SwissProt: P04591 (HIV-1 HXB2 GAG)
EMBL: K03455; AAB50258.1 [EMBL/GenBank/DDBJ]

PIR: UNKNOWN
HIV: K03455; UNKNOWN$HXB2
InterPro: IPR000721
Pfam: PF00607
Prints: none
ProDom: PD000209 (1 - 28) / PD460115 (1 - 57) / PD003398 (1 - 95) / PD613442 (1 - 28) / PD006198 (13 - 85)
PD579426 (29 - 64) / PD401881 (43 - 102) / PD000278 (61 - 132) / PD000267 (148 - 231)
SCOP: SSF47943 Retroviral Core Antigen N-terminus / SSF47353 Retroviral Core Antigen N-terminus
BLOCKS: P04591
Prosite: P04591
ProtoNet: P04591
ProtoMap: P04591
PRESAGE: P04591
Database of Interacting Proteins: P04591
ModBase: P04591
Swiss-2DPAGE: 2D gel

BioAfrica Tools:
- Gag Protein Data Mining Tool provides real-time analysis of HIV-1 Gag isolates
- HIV Structure BLAST searches for similar HIV sequences that have known structures
- HIV Proteomics Resource contains protein sequence and structure analysis tools

Reviews and References: [TOP]

Cite the resource by citing the following paper:
Doherty R et al. BioAfrica's HIV-1 Proteomics Resource: Combining protein data with bioinformatics tools. Retrovirology (2005), 9;2(1):18.

1 - HIV Sequence Compendium 2000
Kuiken CL, Foley B, Hahn B, Korber B, Marx PA, McCutchan F, Mellors JW, Mullins JI, Sodroski J, Wolinksy S.
Theoretical Biol. & Biophys. Group, Los Alamos Nat Lab, LA-UR 01-3860 [Read it online: Compendium]
2 - Retroviruses
Coffin JM, Hughes SH, Varmus HE.
CD-ROM ed. (2002) Cold Spring Harbor Laboratory Press [Read it online: NCBI Bookshelf]
3 - Molecular Characteristics of HIV-1 Subtype C Viruses from KwaZulu-Natal, South Africa:
Implications for Vaccine and Antiretroviral Control Strategies.
Gordon M, De Oliveira T, Bishop K, Coovadia HM, Madurai L, Engelbrecht S, Janse van Rensburg E, Mosam A, Smith A, Cassol S.
Journal of Virology 77(4): 2587-2599 (2003) [pubmed: 12551997]
4 - Specific incorporation of cyclophilin A into HIV-1 virions.
Franke EK, Yuan HE, Luban J.
Nature 372: 359-362 (1994) [pubmed: 7969494]
5 - Functional association of cyclophilin A with HIV-1 virions.
Thali M, Bukovsky A, Kondo E.
Nature 372: 363-365 (1994) [pubmed: 7969495]
6 - Inhibition of HIV-1 replication by cyclosporine A or related compounds correlates with the ability
to disrupt the Gag-cyclophilin A interaction.
Franke EK, Luban J.
Virology 222: 279-282 (1996) [pubmed: 8806510]
7 - The structural biology of HIV assembly.
Ganser-Pornillos BK, Yeager M, Sundquist WI.
Curr Opin Struct Biol. 18(2):203-17 (2008) [pubmed: 18406133]



Page last updated by Tulio de Oliveira.