Sequence analysis of the gliding protein Gli349 in Mycoplasma mobile.
Sequence analysis of the gliding protein Gli349 in Mycoplasma mobile.
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DOI：
10.2142/biophysics.1.33
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发表时间：
2005-01-01
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影响因子：
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通讯作者：
Go, Nobuhiro
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作者：
Metsugi, Shoichi;Uenoyama, Atsuko;Go, Nobuhiro
支原体移动的的运动机制仍不清楚，但据信与任何先前在细菌中鉴定的机制不同。Gli349为M.已知移动的负责对玻璃表面的粘附性和移动性。因此，我们进行了序列分析的Gli349及其同源物MYPU 2110从M。来解读它们的结构我们发现“YxxxxxGF”基序在Gli349中出现了11次，在MYPU 2110中出现了16次。序列的进一步分析显示，Gli349含有18个重复，每个重复约100个氨基酸残基，MYPU 2110含有22个。在NCBI RefSeq非冗余序列数据库中没有发现与任何重复序列同源的序列，并且在已知蛋白质结构中没有发现相容的折叠结构，这表明在Gli349和MYPU 2110中发现的重复序列是新的，并且具有新的折叠结构。使用糜蛋白酶的Gli349的蛋白水解揭示了切割位置通常位于重复序列之间，这意味着连接重复序列的区域是非结构化的，柔性的并且暴露于溶剂。假设每个重复折叠成一个结构域，我们构建了一个模型的Gli349，很好地适合与电子显微镜获得的图像的形状和大小。
The motile mechanism of Mycoplasma mobile remains unknown but is believed to differ from any previously identified mechanism in bacteria. Gli349 of M. mobile is known to be responsible for both adhesion to glass surfaces and mobility. We therefore carried out sequence analyses of Gli349 and its homolog MYPU2110 from M. pulmonis to decipher their structures. We found that the motif "YxxxxxGF" appears 11 times in Gli349 and 16 times in MYPU2110. Further analysis of the sequences revealed that Gli349 contains 18 repeats of about 100 amino acid residues each, and MYPU2110 contains 22. No sequence homologous to any of the repeats was found in the NCBI RefSeq non-redundant sequence database, and no compatible fold structure was found among known protein structures, suggesting that the repeat found in Gli349 and MYPU2110 is novel and takes a new fold structure. Proteolysis of Gli349 using chymotrypsin revealed that cleavage positions were often located between the repeats, implying that regions connecting repeats are unstructured, flexible and exposed to the solvent. Assuming that each repeat folds into a structural domain, we constructed a model of Gli349 that fits well the shape and size of images obtained with electron microscopy.