帶尾噬菌體的形態(tài)一般從一個(gè)空衣殼或者原衣殼開始組裝,，然后噬菌體基因組插入到這個(gè)預(yù)備蛋白殼中?；蚪M包裝的過程要考慮熵和靜電的作用,，以及DNA必須克服的彎曲能。事實(shí)上,，噬菌體DNA的裝運(yùn)泵是眾所周知的最強(qiáng)大的生物泵,。裝運(yùn)一般由一個(gè)分子馬達(dá)驅(qū)動，將ATP水解得到的能量轉(zhuǎn)換為DNA的運(yùn)動能量,。
8月6日《結(jié)構(gòu)》（Structure）雜志的封面文章,，報(bào)道了Morais等人描繪的噬菌體29DNA裝運(yùn)泵不同部分的分子排列與分子衣殼的情況。已有的研究數(shù)據(jù)表明,，低溫電子顯微鏡可以描繪出噬菌體29的DNA裝運(yùn)泵的相對位置,，12重對稱的頭-尾連接器的分子邊界，以及5重對稱的pRNA,、供能的ATP酶和分子衣殼,。
Morais等人發(fā)現(xiàn)，分子改造可能由5重對稱體構(gòu)成,，包括含174堿基,、120堿基和71堿基等等。這些結(jié)構(gòu)與pRNA和ATP酶在原衣殼的頂端周圍形成的五聚體泵部分一致,。所這些研究成果表明了裝運(yùn)泵的組裝途徑與DNA移動到空的原衣殼中的分子機(jī)制,。（生物谷Bioon.com）
生物谷推薦原始出處：
Structure，Vol 16, 1267-1274, 06 August 2008,，Marc C. Morais, Michael G. Rossmann
Defining Molecular and Domain Boundaries in the Bacteriophage 29 DNA Packaging Motor
Marc C. Morais, Jaya S. Koti,Valorie D. Bowman,Emilio Reyes-Aldrete,Dwight L. Anderson,and Michael G. Rossmann
Cryo-electron microscopy (cryo-EM) studies of the bacteriophage 29 DNA packaging motor have delineated the relative positions and molecular boundaries of the 12-fold symmetric head-tail connector, the 5-fold symmetric prohead RNA (pRNA), the ATPase that provides the energy for packaging, and the procapsid. Reconstructions, assuming 5-fold symmetry, were determined for proheads with 174-base, 120-base, and 71-base pRNA; proheads lacking pRNA; proheads with ATPase bound; and proheads in which the packaging motor was missing the connector. These structures are consistent with pRNA and ATPase forming a pentameric motor component around the unique vertex of proheads. They suggest an assembly pathway for the packaging motor and a mechanism for DNA translocation into empty proheads.
