PMID- 23221553
OWN - NLM
STAT- MEDLINE
DCOM- 20130322
LR  - 20211021
IS  - 1098-5514 (Electronic)
IS  - 0022-538X (Print)
IS  - 0022-538X (Linking)
VI  - 87
IP  - 4
DP  - 2013 Feb
TI  - Betaretroviral envelope subunits are noncovalently associated and restricted to 
      the mammalian class.
PG  - 1937-46
LID - 10.1128/JVI.01442-12 [doi]
AB  - The structure of the transmembrane subunit (TM) of the retroviral envelope 
      glycoprotein (Env) is highly conserved among most retrovirus genera and includes 
      a pair of cysteines that forms an intramolecular disulfide loop within the 
      ectodomain. Alpha-, gamma-, and deltaretroviruses have a third cysteine, adjacent 
      to the loop, which forms a disulfide bond between TM and the surface subunit (SU) 
      of Env, while lentiviruses, which have noncovalently associated subunits, lack 
      this third cysteine. The Betaretrovirus genus includes Jaagsiekte sheep 
      retrovirus (JSRV) and mouse mammary tumor virus (MMTV), as well as many 
      endogenous retroviruses. Envelope subunit association had not been characterized 
      in the betaretroviruses, but lack of a third cysteine in the TM ectodomain 
      suggested noncovalently associated subunits. We tested the Env proteins of JSRV 
      and MMTV, as well as human endogenous retrovirus K (HERV-K)108--a 
      betaretrovirus-like human endogenous retrovirus--for intersubunit bonding and 
      found that, as in the lentiviruses, the Env subunits lack an intersubunit 
      disulfide bond. Since these results suggest that the number of cysteines in the 
      TM loop region readily distinguishes between covalent and noncovalent structure, 
      we surveyed endogenous retroviral TM sequences in the genomes of vertebrates 
      represented in public databases and found that (i) retroviruses with 
      noncovalently associated subunits have been present during all of anthropoid 
      evolution and (ii) the noncovalent env motif is limited to mammals, while the 
      covalent type is found among five vertebrate classes. We discuss implications of 
      these findings for retroviral evolution, cross-species transmissions, and 
      recombination events involving the env gene.
FAU - Henzy, Jamie E
AU  - Henzy JE
AD  - Tufts University School of Medicine, Department of Molecular Biology and 
      Microbiology, Boston, Massachusetts, USA.
FAU - Coffin, John M
AU  - Coffin JM
LA  - eng
GR  - R37 CA089441/CA/NCI NIH HHS/United States
PT  - Journal Article
DEP - 20121205
PL  - United States
TA  - J Virol
JT  - Journal of virology
JID - 0113724
RN  - 0 (Disulfides)
RN  - 0 (Protein Subunits)
RN  - 0 (Viral Envelope Proteins)
RN  - K848JZ4886 (Cysteine)
SB  - IM
MH  - Animals
MH  - Computational Biology
MH  - Cysteine/chemistry/genetics
MH  - Disulfides
MH  - Endogenous Retroviruses/*chemistry/genetics
MH  - Humans
MH  - Jaagsiekte sheep retrovirus/*chemistry/genetics
MH  - Mammary Tumor Virus, Mouse/*chemistry/genetics
MH  - Protein Binding
MH  - Protein Subunits/chemistry
MH  - Viral Envelope Proteins/*chemistry
PMC - PMC3571459
EDAT- 2012/12/12 06:00
MHDA- 2013/03/23 06:00
PMCR- 2013/08/01
CRDT- 2012/12/11 06:00
PHST- 2012/12/11 06:00 [entrez]
PHST- 2012/12/12 06:00 [pubmed]
PHST- 2013/03/23 06:00 [medline]
PHST- 2013/08/01 00:00 [pmc-release]
AID - JVI.01442-12 [pii]
AID - 01442-12 [pii]
AID - 10.1128/JVI.01442-12 [doi]
PST - ppublish
SO  - J Virol. 2013 Feb;87(4):1937-46. doi: 10.1128/JVI.01442-12. Epub 2012 Dec 5.