Mycoplasma bovis causes serious infections in ruminants, leading to huge economic losses. Lipoproteins are key components of the mycoplasma membrane and are believed to function in nutrient acquisition, adherence, enzymatic interactions with the host, and induction of the host’s immune response to infection. Many genes of M. bovis have not been assigned functions, in part because of their low sequence similarity with other bacteria, making it difficult to extrapolate gene functions. This study examined functions of a surface-localized leucine-rich repeat (LRR) lipoprotein encoded by mbfN of M. bovis PG45. Homologs of MbfN were detected as 48-kDa peptides by Western blotting in all the strains of M. bovis included in this study, with the predicted 70-kDa full-length polypeptide detected in some strains. Sequence analysis of the gene revealed the absence in some strains of a region encoding the carboxyl-terminal 147 amino acids found in strain PG45, which could account for the variation detected by immunoblotting. In silico analysis of MbfN suggested that it may have an adhesion-related function. In vitro binding assays confirmed MbfN to be a fibronectin and heparin-binding protein. Disruption of mbfN in M. bovis PG45 significantly reduced (P = 0.033) the adherence of M. bovis PG45 to MDBK cells in vitro, demonstrating the role of MbfN as an adhesin.

中文翻译：

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牛支原体mbfN编码一种新型LRR脂蛋白，该蛋白进行蛋白水解加工并结合宿主细胞外基质成分

牛支原体引起反刍动物的严重感染，导致巨大的经济损失。脂蛋白是支原体膜的关键成分，被认为在营养获取，粘附，与宿主的酶相互作用以及诱导宿主对感染的免疫反应中起作用。牛分枝杆菌的许多基因尚未分配功能，部分原因是它们与其他细菌的序列相似性低，因此难以外推基因功能。本研究的表面局部富含亮氨酸重复的功能（LRR）脂蛋白编码由mbfN的牛分枝杆菌PG45。通过Western印迹在所有牛分枝杆菌菌株中检测到MbfN的同源物为48 kDa肽。包括在这项研究中，并在某些菌株中检测到了预测的70 kDa全长多肽。基因的序列分析表明，在某些菌株中不存在编码在PG45菌株中发现的羧基末端147个氨基酸的区域，这可以解释通过免疫印迹检测到的变异。在计算机上对MbfN的分析表明，它可能具有与粘附有关的功能。体外结合测定法证实MbfN是纤连蛋白和肝素结合蛋白。破坏mbfN在牛分枝杆菌PG45显著减少（P = 0.033）的粘附牛分枝杆菌PG45到MDBK细胞在体外，证明MbfN的作用，作为粘附素。