کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
2185192 | 1095964 | 2011 | 15 صفحه PDF | دانلود رایگان |
Many prokaryotic and eukaryotic double-stranded DNA viruses use a scaffolding protein to assemble their capsid. Assembly of the double-stranded DNA bacteriophage P22 procapsids requires the interaction of 415 molecules of coat protein and 60–300 molecules of scaffolding protein. Although the 303-amino-acid scaffolding protein is essential for proper assembly of procapsids, little is known about its structure beyond an NMR structure of the extreme C-terminus, which is known to interact with coat protein. Deletion mutagenesis indicates that other regions of scaffolding protein are involved in interactions with coat protein and other capsid proteins. Single-cysteine and double-cysteine variants of scaffolding protein were generated for use in fluorescence resonance energy transfer and cross-linking experiments designed to probe the conformation of scaffolding protein in solution and within procapsids. We showed that the N-terminus and the C-terminus are proximate in solution, and that the middle of the protein is near the N-terminus but not accessible to the C-terminus. In procapsids, the N-terminus was no longer accessible to the C-terminus, indicating that there is a conformational change in scaffolding protein upon assembly. In addition, our data are consistent with a model where scaffolding protein dimers are positioned parallel with one another with the associated C-termini.
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► The conformation of scaffolding protein was studied in solution and inside procapsids.
► Our study used fluorescence resonance energy transfer and cross-linking to examine the structure.
► The N-terminus is modeled in proximity to both the C-terminus and a middle domain.
► Inside procapsids, scaffolding protein rearranges to a more open conformation.
► Scaffolding proteins are arranged in parallel inside procapsids.
Journal: Journal of Molecular Biology - Volume 410, Issue 2, 8 July 2011, Pages 226–240