Conformation of the Principal Neutralizing Determinant of Human Immunodeficiency Virus Type 1 in Complex with an Anti-gp120 Virus Neutralizing Antibody Studied by Two-Dimensional Nuclear Magnetic Reso
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- 作者：Anat Zvi ; Daniel J. Feigelson ; Yehezkiel Hayek ; and Jacob Anglister
- 刊名：Biochemistry
- 出版年：1997
- 出版时间：July 15, 1997
- 年：1997
- 卷：36
- 期：28
- 页码：8619 - 8627
- 全文大小：222K
- 年卷期：v.36,no.28(July 15, 1997)
- ISSN：1520-4995
文摘
The principal neutralizing determinant (PND) of humanimmunodeficiency virus type 1 (HIV-1) is located in the third hypervariable region (V3) of the virusenvelope glycoprotein gp120. Theconformation of a V3 peptide of HIV-1IIIB bound to the Fabfragment of an anti-gp120 HIV neutralizingantibody, 0.5
, was studied by 1H NMR spectroscopy.This 18-residue peptide represents the epitoperecognized by 0.5 and encompasses most of the PND. The slowoff-rate of the peptide prevents theobservation of peptide/Fab interactions as well as intramolecularinteractions within the bound peptide bytransferred nuclear Overhauser enhancement (TRNOE). To detect andassign interactions within the boundpeptide in the 52 kDa complex, NOESY difference spectra were measuredusing three strategies: (a)deuteration of peptide residues, (b) Arg 
Lys replacements, and (c)truncation of the peptide antigen.Each difference spectrum was calculated between NOESY spectrameasured for two Fab complexes inwhich the bound peptides differed in their deuteration or in theirsequence. The difference spectra revealednumerous interactions between the N-terminus of the epitope (Arg-4,Lys-5, Ser-6, Ile-7, and Ile-9) andits C-terminus (Phe-17, Val-18, Thr-19, and Ile-20). The assignedNOE interactions within the boundpeptide were translated into distance restraints that were used tocalculate the conformation of the boundpeptide by the hybrid distance geometry/simulated annealing method.A total of 39 long-range (residuesi - j > 4), 14 short-range, and 69intraresidue NOE interactions within the bound peptide havebeenassigned. Twelve structures without NOE constraint violations wereobtained, having a 1.6 Å rms deviationfor the backbone atoms. The peptide forms a 10-residue loop, whilethe two segments flanking this loop,KSI and VTI, interact extensively with each other and possibly formantiparallel -strands. This loopconformation could be observed due to the unusual large size (17residues) of the antigenic determinantrecognized by 0.5.
, was studied by 1H NMR spectroscopy.This 18-residue peptide represents the epitoperecognized by 0.5 and encompasses most of the PND. The slowoff-rate of the peptide prevents theobservation of peptide/Fab interactions as well as intramolecularinteractions within the bound peptide bytransferred nuclear Overhauser enhancement (TRNOE). To detect andassign interactions within the boundpeptide in the 52 kDa complex, NOESY difference spectra were measuredusing three strategies: (a)deuteration of peptide residues, (b) Arg Lys replacements, and (c)truncation of the peptide antigen.Each difference spectrum was calculated between NOESY spectrameasured for two Fab complexes inwhich the bound peptides differed in their deuteration or in theirsequence. The difference spectra revealednumerous interactions between the N-terminus of the epitope (Arg-4,Lys-5, Ser-6, Ile-7, and Ile-9) andits C-terminus (Phe-17, Val-18, Thr-19, and Ile-20). The assignedNOE interactions within the boundpeptide were translated into distance restraints that were used tocalculate the conformation of the boundpeptide by the hybrid distance geometry/simulated annealing method.A total of 39 long-range (residuesi - j > 4), 14 short-range, and 69intraresidue NOE interactions within the bound peptide havebeenassigned. Twelve structures without NOE constraint violations wereobtained, having a 1.6 Å rms deviationfor the backbone atoms. The peptide forms a 10-residue loop, whilethe two segments flanking this loop,KSI and VTI, interact extensively with each other and possibly formantiparallel -strands. This loopconformation could be observed due to the unusual large size (17residues) of the antigenic determinantrecognized by 0.5.