       Document 0710
 DOCN  M9640710
 TI    Spectroscopic study of an HIV-1 capsid protein major homology region
       peptide analog.
 DT    9604
 AU    Clish CB; Peyton DH; Barklis E; Department of Chemistry, Portland State
       University, OR; 97207-0751, USA.
 SO    FEBS Lett. 1996 Jan 2;378(1):43-7. Unique Identifier : AIDSLINE
       MED/96140705
 AB    The capsid (CA) domain of retroviral Gag proteins possesses one
       subdomain, the major homology region (MHR), which is conserved among
       nearly all avian and mammalian retroviruses. While it is known that the
       mutagenesis of residues in the MHR will impair virus infectivity, the
       precise structure and function of the MHR is not known. In order to
       obtain further information on the MHR, we have examined the structure of
       a synthetic peptide encompassing the MHR of human immunodeficiency virus
       type I (HIV-1) CA protein. Multiple sequence alignment and secondary
       structure prediction indicate that the peptide could form 50%
       alpha-helix and 10% beta-sheet. In addition, circular dichroism studies
       indicate that, in the presence of 50% trifluoroethanol (TFE), the
       peptide adopts an alpha-helical structure over half of its length.
       Further analysis by proton nuclear magnetic resonance spectroscopy
       suggests that the C-terminal portion of the MHR forms a helix in aqueous
       solution. Upon the addition of TFE, the position of the helix remains
       nearly constant, but the magnitude of the changes in H alpha chemical
       shifts of the residues indicate a more stable helix. These results
       suggest that a helical C-terminus of retroviral MHRs may be integral to
       the function of this region.
 DE    Amino Acid Sequence  Capsid/*CHEMISTRY  Circular Dichroism
       HIV-1/*CHEMISTRY  Molecular Sequence Data  Nuclear Magnetic Resonance
       Protein Structure, Secondary  *Sequence Homology  Support, Non-U.S.
       Gov't  Trifluoroethanol/PHARMACOLOGY  JOURNAL ARTICLE

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).

