DNA Recognition during DNA Packaging by the Lambda-like Bacteriophages: Sites and Proteins

在大的双链DNA病毒中，如疱疹病毒和尾随噬菌体，病毒DNA是通过包装酶(称为终止酶)和病毒DNA中的特定识别位点相互作用来识别包装的。在类lambda噬菌体中，这些识别位点位于一段名为cos的约200bp的DNA片段中。COS包含几个亚位点，包括COSB和CoSN，COSB是终止酶结合位点，CoSN是终止酶切割DNA形成单位长度DNA分子的位点。本研究调查了位于CoSN和COSB之间的一个新发现的亚位点的功能。新的地点包括DNA弯曲的可能性将被确定。是否在DNA包装的开始和/或结束时需要新的位置将被研究。在类lambda噬菌体的cos中，末端酶结合位点很大且复杂，有三个末端酶结合位点。由于这种复杂性，lambda的末端在cos上形成了一个复杂的DNA-蛋白质复合体。噬菌体N15是一种类Lambda病毒。N15的终止酶结合部位非常简单--只有一个终止酶结合部位。一个主要的问题是N15终止酶是否形成了一个复杂的DNA-蛋白质复合体，或者N15识别是否与lambda识别有根本的不同。关于N15终止酶如何与N15的cos结合的实验将为dsDNA病毒的DNA识别提供重要的见解。这项研究项目将为来自不同背景的几名本科生提供具有挑战性的研究经验。这项工作对于理解dsDNA病毒是如何包装病毒DNA具有普遍意义。

In the large double-stranded DNA viruses, such as the herpes viruses and the tailed bacteriophages, viral DNA is recognized for packaging thru the interactions of a packaging enzyme, called terminase, and specific recognition sites in the viral DNA. In the lambda-like bacteriophages, these recognition sites are located in an approximately 200 bp-long DNA segment called cos. cos contains several subsites, including cosB, the terminase binding site, and cosN, the site where terminase cuts the DNA to make unit-length DNA molecules. This research investigates the function of a newly-discovered subsite located between cosN and cosB. The possibility that the new site includes a DNA bend will be determined. Whether the new site is needed at the start and/or the end of DNA packaging will be studied. The terminase binding site in the cos of the paradigm lambda-like bacteriophage, lambda, is large and complex, with three binding sites for terminase. Because of this complexity, the terminase of lambda forms a complicated DNA-protein complex on cos. Bacteriophage N15 is a lambda-like virus. The terminase binding site for N15 is very simple -- there is only one terminase binding site. A major question is whether N15 terminase forms a complicated DNA-protein complex, or whether N15 recognition differs fundamentally from lambda recognition. Experiments on how N15 terminase binds the cos of N15 will give important insights into DNA recognition in the dsDNA viruses. This research project will provide challenging research experiences to several undergraduates from diverse backgrounds. The work is of general significance for understanding how dsDNA viruses package viral DNA.