3b63

<table><tr><td colspan='2'>[[3b63]] is a 14 chain structure with sequence from [http://en.wikipedia.org/wiki/Limulus_polyphemus Limulus polyphemus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3B63 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3B63 FirstGlance]. <br>

</td></tr><tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[3b5u|3b5u]]</td></tr>

<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3b63 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3b63 OCA], [http://pdbe.org/3b63 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=3b63 RCSB], [http://www.ebi.ac.uk/pdbsum/3b63 PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=3b63 ProSAT]</span></td></tr>

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== Publication Abstract from PubMed ==

Actin carries out many of its cellular functions through its filamentous form; thus, understanding the detailed structure of actin filaments is an essential step in achieving a mechanistic understanding of actin function. The acrosomal bundle in the Limulus sperm has been shown to be a quasi-crystalline array with an asymmetric unit composed of a filament with 14 actin-scruin pairs. The bundle in its true discharge state penetrates the jelly coat of the egg. Our previous electron crystallographic reconstruction demonstrated that the actin filament cross-linked by scruin in this acrosomal bundle state deviates significantly from a perfect F-actin helix. In that study, the tertiary structure of each of the 14 actin protomers in the asymmetric unit of the bundle filament was assumed to be constant. In the current study, an actin filament atomic model in the acrosomal bundle has been refined by combining rigid-body docking with multiple actin crystal structures from the Protein Data Bank and constrained energy minimization. Our observation demonstrates that actin protomers adopt different tertiary conformations when they form an actin filament in the bundle. The scruin and bundle packing forces appear to influence the tertiary and quaternary conformations of actin in the filament of this biologically active bundle.

 

 

== References ==

<references/>

[[Category: Chiu, W]]

[[Category: Cong, Y]]

[[Category: Dougherty, M]]

[[Category: Matsudaira, P]]

[[Category: Sali, A]]

[[Category: Schmid, M F]]

[[Category: Topf, M]]

[[Category: Structural protein]]