在霍乱弧菌O1血清群中，rfaD与rfb操纵子紧密相连。

In Vibrio cholerae serogroup O1, rfaD is closely linked to the rfb operon.

作者信息

Stroeher U H, Karageorgos L E, Morona R, Manning P A

机构信息

Department of Microbiology and Immunology, University of Adelaide, Australia.

出版信息

Gene. 1995 Mar 21;155(1):67-72. doi: 10.1016/0378-1119(94)00923-g.

DOI:10.1016/0378-1119(94)00923-g

PMID:7698669

Abstract

The rfaD gene of Escherichia coli encodes ADP-L-glycero-D-mannoheptose-6- epimerase, an enzyme required for the biosynthesis of the lipopolysaccharide (LPS) precursor ADP-L-glycero-D- mannoheptose, associated with production of the core oligosaccharide. We have identified an rfaD homologue in Vibrio cholerae O1. This gene maps adjacent to the rfb region encoding O-antigen biosynthesis, but is transcribed divergently. The complete nucleotide sequence of rfaD and the flanking DNA has been determined, and rfaD would appear to be the only gene homologous to known LPS core biosynthesis genes in this region. Comparison with the E. coli rfaD shows many similar structural features such as the ADP-binding beta alpha beta fold at the N terminus, as well as a high degree of homology of both the nucleotide and amino-acid sequences. Based on homology, rfaD of V. cholerae may be transcribed using both sigma 70- and sigma 54-dependent promoters.

摘要

大肠杆菌的rfaD基因编码ADP-L-甘油-D-甘露庚糖-6-表异构酶，该酶是脂多糖（LPS）前体ADP-L-甘油-D-甘露庚糖生物合成所必需的，与核心寡糖的产生相关。我们在霍乱弧菌O1中鉴定出了一个rfaD同源物。该基因定位于编码O抗原生物合成的rfb区域附近，但转录方向相反。已确定rfaD及其侧翼DNA的完整核苷酸序列，并且rfaD似乎是该区域中与已知LPS核心生物合成基因同源的唯一基因。与大肠杆菌rfaD的比较显示出许多相似的结构特征，例如N端的ADP结合β-α-β折叠，以及核苷酸和氨基酸序列的高度同源性。基于同源性，霍乱弧菌的rfaD可能使用依赖于σ70和σ54的启动子进行转录。