Evolution of Intradiol Dioxygenase Genes in Bacteria

该研究计划旨在探索如何属性的 基因和基因内区域的稳定性受到以下因素的影响： 相邻的DNA序列 细菌内二醇双加氧酶 研究对象的基因有着共同的祖先 在他们的生活中经历了无数次的重新安排， 进化分歧 重组可能会 导致独立转录的 基因，但不同的加氧酶基因的染色体位置 在不同的超操纵子簇中是保守的。 有利于基因聚集的选择力将是 通过检查生理和遗传后果来探索 定向转座的加氧酶基因从一个集群， 另 转座会导致遗传不稳定， 不稳定性的可能来源是序列定向突变， 可能导致DNA区域之间缺失的过程 序列重复 序列导向的 突变发生将通过比较DNA 经过自发突变的基因序列 无论是在其正常位置或后换位到一个 不同的集群。 导致序列导向的 突变也可能有助于基因修复， 可能性将探讨通过分析的DNA序列， 容易恢复的突变 氧气的酶促活化是 一个基本的生物学过程， 加氧酶将增加我们对生物化学步骤的理解 引导分子氧同化成有机物 印刷受体. 我们计划分离出突变的加氧酶， 功能性的，但改变了底物特异性或催化活性。 效率， 对这些蛋白质的分析可能会提供 对加氧酶与它们之间相互作用的新见解 印刷受体.

The research program is designed to explore how the properties of genes and the stability of regions within genes are influenced by neighboring DNA sequences. Bacterial intradiol dioxygenase genes, the subjects of the investigation, share common ancestry and have undergone numerous rearrangements during their evolutionary divergence. Rearrangements might be expected to lead to the physical separation of independently transcribed genes, but the chromosomal position of divergent oxygenase genes has been conserved within different supraoperonic clusters. Selective forces favoring the clustering of genes will be explored by examining the physiological and genetic consequences of directed transposition of oxygenase genes from one cluster to another. Transposition can lead to genetic instability, and a possible source of instability is sequence-directed mutation, a process that can lead to deletions between regions of DNA sequence repetition. The extent to which sequence-directed mutations occur will be explored by comparison of the DNA sequences of genes that have undergone spontaneous mutation either in their normal location or after transposition to a different cluster. Processes that lead to sequence-directed mutation also might contribute to genetic repair, and this possibility will be explored by analysis of DNA sequence of mutations that revert readily. Enzymatic activation of oxygen is a fundamental biological process, and the genetic analysis of oxygenases will increase our understanding of biochemical steps that direct the assimilation of molecular oxygen into organic substrates. We plan to isolate mutant oxygenases that are functional but altered in substrate specificity or in catalytic efficiency,. Analysis of these proteins is likely to provide novel insight into interactions between oxygenases and their substrates.