2fs3: Difference between revisions

[[Image:2fs3.gif|left|200px]]<br /><applet load="2fs3" size="350" color="white" frame="true" align="right" spinBox="true"  

Maturation of the bacteriophage HK97 capsid from a precursor (Prohead II) to the mature state (Head II) involves a 60 A radial expansion. The mature particle is formed by 420 copies of the major capsid protein organized on a T = 7 laevo lattice with each subunit covalently crosslinked to two neighbors. Well-characterized pH 4 expansion intermediates make HK97 valuable for investigating quaternary structural dynamics. Here, we use X-ray crystallography and cryo-EM to demonstrate that in the final transition in maturation (requiring neutral pH), pentons in Expansion Intermediate IV (EI-IV) reversibly sample 14 A translations and 6 degrees rotations relative to a fixed hexon lattice. The limit of this trajectory corresponds to the Head II conformation that is secured at this extent only by the formation of the final class of covalent crosslinks. Mutants that cannot crosslink or EI-IV particles that have been rendered incapable of forming the final crosslink remain in the EI-IV state.

2FS3 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Enterobacteria_phage_hk620 Enterobacteria phage hk620]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2FS3 OCA].  

[[Category: Conway, J F.]]

[[Category: Duda, R L.]]

[[Category: Firek, B A.]]

[[Category: Hendrix, R W.]]

[[Category: Johnson, J E.]]

[[Category: Speir, J A.]]

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