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Mapping the interaction between the cytoplasmic domains of HIV ‐1 viral protein U and human CD 4 with NMR spectroscopy
Author(s) -
Singh Sameer K.,
Möckel Luis,
ThiagarajanRosenkranz Pallavi,
Wittlich Marc,
Willbold Dieter,
Koenig Bernd W.
Publication year - 2012
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2012.08732.x
Subject(s) - endoplasmic reticulum , cytoplasm , transmembrane domain , nuclear magnetic resonance spectroscopy , chemistry , amino acid , cytosol , transmembrane protein , peptide sequence , biophysics , microbiology and biotechnology , biochemistry , biology , receptor , stereochemistry , gene , enzyme
Viral protein U ( V p U ) of HIV ‐1 plays an important role in downregulation of the main HIV ‐1 receptor CD 4 from the surface of infected cells. Physical binding of V p U to newly synthesized CD 4 in the endoplasmic reticulum is an early step in a pathway leading to proteasomal degradation of CD 4. In this study, regions in the cytoplasmic domain of V p U involved in CD 4 binding were identified by NMR spectroscopy. Amino acids in both helices found in the cytoplasmic region of V p U in membrane‐mimicking detergent micelles experience chemical shift perturbations upon binding to CD 4, whereas amino acids between the two helices and at the C ‐terminus of V p U show no or only small changes, respectively. The topology of the complex was further studied with paramagnetic relaxation enhancement. Paramagnetic spin labels were attached at three sequence positions of a CD 4 peptide comprising the transmembrane and cytosolic domains of the receptor. V p U binds to a membrane‐proximal region in the cytoplasmic domain of CD 4. Structured digital abstractVpU and CD4 bind by nuclear magnetic resonance ( View interaction )