کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6140979 | 1227190 | 2013 | 12 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Revolution rather than rotation of AAA+ hexameric phi29 nanomotor for viral dsDNA packaging without coiling
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موضوعات مرتبط
علوم زیستی و بیوفناوری
ایمنی شناسی و میکروب شناسی
ویروس شناسی
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![عکس صفحه اول مقاله: Revolution rather than rotation of AAA+ hexameric phi29 nanomotor for viral dsDNA packaging without coiling Revolution rather than rotation of AAA+ hexameric phi29 nanomotor for viral dsDNA packaging without coiling](/preview/png/6140979.png)
چکیده انگلیسی
It has long been believed that the DNA-packaging motor of dsDNA viruses utilizes a rotation mechanism. Here we report a revolution rather than rotation mechanism for the bacteriophage phi29 DNA packaging motor. The phi29 motor contains six copies of the ATPase (Schwartz et al., this issue); ATP binding to one ATPase subunit stimulates the ATPase to adopt a conformation with a high affinity for dsDNA. ATP hydrolysis induces a new conformation with a lower affinity, thus transferring the dsDNA to an adjacent subunit by a power stroke. DNA revolves unidirectionally along the hexameric channel wall of the ATPase, but neither the dsDNA nor the ATPase itself rotates along its own axis. One ATP is hydrolyzed in each transitional step, and six ATPs are consumed for one helical turn of 360°. Transition of the same dsDNA chain along the channel wall, but at a location 60° different from the last contact, urges dsDNA to move forward 1.75 base pairs each step (10.5 bp per turn/6ATP=1.75 bp per ATP). Each connector subunit tilts with a left-handed orientation at a 30° angle in relation to its vertical axis that runs anti-parallel to the right-handed dsDNA helix, facilitating the one-way traffic of dsDNA. The connector channel has been shown to cause four steps of transition due to four positively charged lysine rings that make direct contact with the negatively charged DNA phosphate backbone. Translocation of dsDNA into the procapsid by revolution avoids the difficulties during rotation that are associated with DNA supercoiling. Since the revolution mechanism can apply to any stoichiometry, this motor mechanism might reconcile the stoichiometry discrepancy in many phage systems where the ATPase has been found as a tetramer, hexamer, or nonamer.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Virology - Volume 443, Issue 1, 15 August 2013, Pages 28-39
Journal: Virology - Volume 443, Issue 1, 15 August 2013, Pages 28-39
نویسندگان
Chad Schwartz, Gian Marco De Donatis, Hui Zhang, Huaming Fang, Peixuan Guo,