Document 0335
 DOCN  M94A0335
 TI    Phosphorescence and optically detected magnetic resonance investigation
       of the binding of the nucleocapsid protein of the human immunodeficiency
       virus type 1 and related peptides to RNA.
 DT    9412
 AU    Lam WC; Maki AH; Casas-Finet JR; Erickson JW; Kane BP; Sowder RC 2nd;
       Henderson LE; Department of Chemistry, University of California, Davis
       95616.
 SO    Biochemistry. 1994 Sep 6;33(35):10693-700. Unique Identifier : AIDSLINE
       MED/94355292
 AB    The RNA and DNA complexes of nucleocapsid protein p7.Zn (NCp7.Zn) of the
       human immunodeficiency virus type 1 (HIV-1) are studied by
       phosphorescence and optically detected magnetic resonance (ODMR). The
       single tryptophan, Trp37, which is located on the C-terminal zinc finger
       domain is used as an intrinsic probe. Reductions in the triplet state
       zero-field splitting (zfs) D parameter of Trp37 upon complex formation
       with poly(I) and poly(U) are observed. These results, in conjunction
       with the phosphorescence red-shifts and triplet state lifetime
       reductions that are observed, suggest the presence of aromatic stacking
       interactions between NCp7.Zn and the bases of the RNA polymers. An
       alteration of the intersystem crossing pattern upon complex formation,
       in addition to the above mentioned spectroscopic shifts, also is
       consistent with previously observed tryptophans that undergo stacking
       interactions with DNA bases [Zang, L.-H., Maki, A.H., Murphy, J.B., &
       Chase, J.W. (1987) Biophys. J. 52, 867-872. Tsao, D.H.H., Casas-Finet,
       J.R., Maki, A.H., & Chase, J.W. (1989) Biophys. J. 55, 927-936]. These
       conclusions support those from a recent ODMR study [Lam, W.-C., Maki,
       A.H., Casas-Finet, J.R., Erickson, J.W., Sowder, R.C., II, & Henderson,
       L.E. (1993) FEBS Lett. 328, 45-48] of NCp7.Zn binding to 5-mercurated
       polyuridylic acid [poly(5-HgU)] in which stacking interactions between
       the RNA and NCp7.Zn are inferred from the observation of an external
       heavy atom effect induced on Trp37.(ABSTRACT TRUNCATED AT 250 WORDS)
 DE    Amino Acid Sequence  Capsid/*METABOLISM  Gene Products, gag/*METABOLISM
       HIV-1/*CHEMISTRY  Luminescence  Molecular Sequence Data  RNA-Binding
       Proteins/*CHEMISTRY  RNA, Viral/*METABOLISM  Spectrum Analysis  Support,
       U.S. Gov't, P.H.S.  *Zinc Fingers  JOURNAL ARTICLE

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