Maximum-entropy calculation of the electron density at 4 A resolution of Pf1 filamentous bacteriophage

Bryan, RK and Bansal, Manju and Folkhard, , W and Nave, C and Marvin , DA (1983) Maximum-entropy calculation of the electron density at 4 A resolution of Pf1 filamentous bacteriophage. In: Proceedings Of The National Academy Of Sciences of the United States of America-Biological Sciences , 80 (15). 4728-4731 .

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Abstract

A 4 A electron-density map of Pf1 filamentous bacterial virus has been calculated from x-ray fiber diffraction data by using the maximum-entropy method. This method produces a map that is free of features due to noise in the data and enables incomplete isomorphous-derivative phase information to be supplemented by information about the nature of the solution. The map shows gently curved (banana-shaped) rods of density about 70 A long, oriented roughly parallel to the virion axis but slewing by about 1/6th turn while running from a radius of 28 A to one of 13 A. Within these rods, there is a helical periodicity with a pitch of 5 to 6 A. We interpret these rods to be the helical subunits of the virion. The position of strongly diffracted intensity on the x-ray fiber pattern shows that the basic helix of the virion is right handed and that neighboring nearly parallel protein helices cross one another in an unusual negative sense.

Item Type:	Journal Article
Publication:	Proceedings Of The National Academy Of Sciences of the United States of America-Biological Sciences
Publisher:	National Academy of Sciences
Additional Information:	Copyright of this article belongs to National Academy of Sciences.
Department/Centre:	Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited:	25 Feb 2011 06:03
Last Modified:	25 Feb 2011 06:03
URI:	http://eprints.iisc.ac.in/id/eprint/35756

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