Three new members of the serine-aspartate repeat protein multigene family of Staphylococcus aureus
Three new members of the serine-aspartate repeat protein multigene family of Staphylococcus aureus
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DOI：
10.1099/00221287-144-12-3387
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发表时间：
1998-12-01
期刊：
影响因子：
--
通讯作者：
Foster, TJ
中科院分区：
文献类型：
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作者：
Josefsson, E;McCrea, KW;Foster, TJ
在金黄色葡萄球菌菌株纽曼中发现了三个新基因，编码含丝氨酸-天冬氨酸（SD）重复序列的蛋白质SdrC、SdrD和SdrE，SD重复序列较早在S.金黄色葡萄球菌纤维蛋白原结合凝集因子ClfA和ClfB基因编码锚定在金黄色葡萄球菌细胞表面的高分子量纤维蛋白原结合蛋白。目前报道的sdr基因是紧密连锁、串联排列的。推测的Sdr蛋白与ClfA和ClfB在结构和序列上都具有相似性。在N端，推测的分泌信号序列位于大约500个残基A区之前。当与家族的任何其他成员比对时，Sdr和Clf蛋白的A区仅显示20- 30%的残基同一性。唯一的保守序列是共有基序TYTFTDYVD。Sdr蛋白与ClfA和ClfB的不同之处在于，在A区和R区之间具有2至5个额外的110-113个残基的重复序列（B基序）。每个B基序包含通常在真核蛋白中发现的共有Ca 2+结合EF-手环。通过bisANS荧光分析显示包含SdrD的5个B重复的重组SdrD（B1-B5）蛋白的结构完整性是Ca 2+依赖的，表明EF-手是功能性的。当Ca 2+被去除时，结构折叠成未折叠的构象。Ca ~（2+）的加入使细胞结构得到恢复。Sdr蛋白的C-末端R-结构域含有132-170个SD残基。这些之后是保守的壁锚定区的特征，许多表面蛋白的革兰氏阳性菌。31株S.金黄色葡萄球菌菌株从人类和牛源进行Southern杂交测试，虽然在少数菌株中，它包含两个而不是三个基因。
Three new genes encoding the serine-aspartate (SD) repeat-containing proteins SdrC, SdrD and SdrE were found in Staphylococcus aureus strain Newman, The SD repeats had earlier been found in the S. aureus fibrinogen-binding clumping factors ClfA and ClfB, The clfA and clfB genes encode high-molecular-mass fibrinogen-binding proteins that are anchored to the cell surface of S. aureus, The sdr genes now reported are closely linked and tandemly arrayed. The putative Sdr proteins have both organizational and sequence similarity to ClfA and ClfB, At the N-terminus, putative secretory signal sequences precede approximately 500 residue A regions. The A regions of the Sdr and Clf proteins exhibit only 20-30 % residue identity when aligned with any other member of the family. The only conserved sequence is the consensus motif TYTFTDYVD, The Sdr proteins differ from ClfA and ClfB by having two to five additional 110-113 residue repeated sequences (B-motifs) located between region A and the R-region, Each B-motif contains a consensus Ca2+-binding EF-hand loop normally found in eukaryotic proteins. The structural integrity of recombinant SdrD(B1-B5) protein comprising the five B-repeats of SdrD was shown by bisANS fluorescence analysis to be Ca2+-dependent, suggesting that the EF-hands are functional. When Ca2+ was removed the structure collapsed to an unfolded conformation. The original structure was restored by addition of Ca2+. The C-terminal R-domains of the Sdr proteins contain 132-170 SD residues. These are followed by conserved wall-anchoring regions characteristic of many surface proteins of Cram-positive bacteria. The sdr locus was present in all 31 S. aureus strains from human and bovine sources tested by Southern hybridization, although in a few strains it contained two rather than three genes.