GAG - Group-specific Antigen protein

HIV GAG encodes the structural capsid proteins. The proteins are produced as a GAG precursor polyprotein, which is processed by viral protease







Matrix - p17
Core Antigen capsid - p24
Nucleocapsid - p7
p6
p2
p1





SwissProt: P04591 (HIV-1 HXB2 Gag)
Chime Tutorial:  not available
Los Alamos HIV structure DB: not available
EMBL: K03455 [EMBL/GenBank/DDBJ]
BioAfrica: Gag Protein Data Mining Tool

Isoforms:

  • p55 - GAG Polyprotein (499 amino acids)
  • p160 - GAG-POL Polyprotein

Cleavage site:

Localization:

  • plasma membrane
  • cytoplasm
  • virion

Function:

  • structural protein
  • membrane-associated Gag attracts two copies of viral RNA along with cellular and viral proteins that trigger budding of virion from surface of cell
  • Protease cleaves the Gag precursor after virion budding (Ref. #5)

Additional Information:

  • the precursor consists of a myristylated protein (p55), which is processed by protease to form Matrix protein (MA - p17), Core Antigen capsid protein (CA - p24), Nucleo-Capsid protein (NC - p7), p6, p2 and p1
    (Ref. #5)
  • Gag precursor protein is translated from unspliced viral mRNA
  • during translation, the N-terminus is Myristoylated (Ref. #4)
  • myristoylation triggers binding to cellular membrane
  • protease cleavage of p55 is the viral maturation process

Genomic Location: [TOP]

Reference Sequences:

HIV-1 (HXB2): 

          10         20         30         40         50         60         70
           |          |          |          |          |          |          |
  GARASVLSGG ELDRWEKIRL RPGGKKKYKL KHIVWASREL ERFAVNPGLL ETSEGCRQIL GQLQPSLQTG 
          80         90        100        110        120        130        140
           |          |          |          |          |          |          |
  SEELRSLYNT VATLYCVHQR IEIKDTKEAL DKIEEEQNKS KKKAQQAAAD TGHSNQVSQN YPIVQNIQGQ 
         150        160        170        180        190        200        210
           |          |          |          |          |          |          |
  MVHQAISPRT LNAWVKVVEE KAFSPEVIPM FSALSEGATP QDLNTMLNTV GGHQAAMQML KETINEEAAE 
         220        230        240        250        260        270        280
           |          |          |          |          |          |          |
  WDRVHPVHAG PIAPGQMREP RGSDIAGTTS TLQEQIGWMT NNPPIPVGEI YKRWIILGLN KIVRMYSPTS 
         290        300        310        320        330        340        350
           |          |          |          |          |          |          |
  ILDIRQGPKE PFRDYVDRFY KTLRAEQASQ EVKNWMTETL LVQNANPDCK TILKALGPAA TLEEMMTACQ 
         360        370        380        390        400        410        420
           |          |          |          |          |          |          |
  GVGGPGHKAR VLAEAMSQVT NSATIMMQRG NFRNQRKIVK CFNCGKEGHT ARNCRAPRKK GCWKCGKEGH 
         430        440        450        460        470        480        490
           |          |          |          |          |          |          |
  QMKDCTERQA NFLGKIWPSY KGRPGNFLQS RPEPTAPPEE SFRSGVETTT PPQKQEPIDK ELYPLTSLRS 
        499 
          | 
  LFGNDPSSQ 
      [download in fasta format]

Length: 499 amino acids
Molecular Weight: 55798 Da
Theoretical pI: 9.18
Protein Domains/Folds/Motifs: [TOP]

p17 - Matrix protein - 131 amino acids (residues 1 - 131)
p24 - Core Antigen capsid protein - 231 amino acids (residues 132 - 362)
p7 - Nucleo-Capsid protein - 55 amino acids (residues 377 - 431)
p6 - 52 amino acids (residues 448 - 499)
p2 - 14 amino acids (residues 363 - 376)
p1 - 16 amino acids (residues 432 - 447)


Secondary Structure prediction:

Coiled-coil Regions - ncoils:


Low Complexity Regions - seg:


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 knuckle motif:
Leucine Zipper motif:

Protein-Protein Interactions: [TOP]

  • HIV protease cleaves GAG
  • Gag binds to Vpr for its incorporation into virion
  • Gag binds to Vif for its incorporation into virion
  • Gag binds to Protease for regulation of protease activity
  • Gag binds to Actin during viral particle assembly
  • Gag binds to Cyclophilin A during Capsid core assembly
Primary and Secondary Database Entries: [TOP]

Identifiers:

PDB/MMDB: Search for HIV-1 & GAG

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

PIR: UNKNOWN
HIV: K03455; GAG$HXB2
InterPro: IPR000071 - Retroviral Matrix p17 family / IPR000721 - Retroviral Nuceocapsid p24 family
IPR001878 - Zinc-finger (CCHC-type) Domain / IPR008916 - Retroviral Core Antigen C-terminal Domain
IPR008919 - Retroviral Core Antigen N-terminal Core Domain
Pfam: PF00540 - Matrix p17 / PF00607 - Nucleocapsid p24 / PF00098 - Zinc-Finger (CCHC-type)
Prints: PR00234 - HIV1MATRIX / PR00939 - Zinc-Finger (CCHC-type)
ProDom: PD000202 (1 - 131) / PD003398 (121 - 226) / PD613442 (123 - 159) / PD000209 (132 - 159)
PD460115 (132 - 188) / PD006198 (144 - 216) / PD579426 (160 - 195) / PD000278 (192 - 263)
PD394824 (263 - 425) / PD000267 (279 - 362) / PD027136 (284 - 414) / PD539915 (311 - 408)
PD488523 (355 - 405) / PD506618 (363 - 413) / PD456461 (363 - 495) / PD000129 (363 - 412)
PD014300 (374 - 428) / PD402044 (384 - 414) / PD319272 (388 - 425) / PD323937 (389 - 480)
PD617862 (390 - 424) / PD086795 (390 - 410) / PD594906 (390 - 456) / PD107922 (391 - 431)
PD185557 (391 - 477) / PD351972 (391 - 428) / PD375076 (391 - 425) / PD019096 (391 - 429)
PD066914 (392 - 495) / PD008985 (412 - 460) / PD406622 (413 - 447) / PD149817 (448 - 485)
PD454601 (448 - 499) / PD425744 (449 - 499) / PD613638 (449 - 496) / PD474283 (449 - 495)
PD612384 (449 - 499)
SCOP: SSF47943 - Retroviral Core Antigen N-terminus / SSF47836 - Retroviral matrix protein
SSF47756 - Retroviral zinc finger-like domains / SSF47353 - Retroviral Core Antigen C-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]

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 - Myristoylation-dependent replication and assembly of human immunodeficiency virus 1.
Bryant M, Ratner L.
Proc Natl Acad Sci USA 87: 523-527 (1990) [pubmed: 2405382]
5 - Role of capsid precursor processing and myristoylation in morphogenesis and infectivity of
human immunodeficiency virus type 1.
Gottlinger HG, Sodroski JG, Haseltine WA.
Proc Natl Acad Sci USA 86: 5781-5785 (1989) [pubmed: 2788277]


Page last updated by Tulio de Oliveira.