Effects of temperature and Y21M mutation on conformational heterogeneity of the major coat protein (pVIII) of filamentous bacteriophage fd

Solid-state NMR spectroscopy was used to analyze the conformational heterog eneity of the major coat protein (pVIII) of filamentous bacteriophage fd. B oth one and two-dimensional solid-state NMR spectra of magnetically aligned samples of fd bacteriophage reveal that an increase in temperature and a s ingle site substitution (Tyr21 to Met, Y21M) reduce the conformational hete rogeneity observed throughout wild-type pVIII. The NMR results are consiste nt with previous studies indicating that conformational flexibility in the hinge-bend segment that links the amphipathic and hydrophobic helices in th e membrane-bound form of the protein plays an essential role during phage a ssembly, which involves a major change in the tertiary, but not secondary, structure of the coat protein. (C) 1999 Academic Press.