White Jacinta F, Peng Yong Y, Ng Xuen, Bartoschek Denis, Glattauer Veronica, Ramshaw John A M
CSIRO Manufacturing, Bayview Avenue, Clayton, VIC 3169, Australia.
CSIRO Manufacturing, Bayview Avenue, Clayton, VIC 3169, Australia.
Micron. 2025 Aug;195:103832. doi: 10.1016/j.micron.2025.103832. Epub 2025 Apr 18.
Various bacterial collagen-like proteins have been previously described and shown to have a triple helical, (Gly-Xaa Yaa) repeating structure. They are stable without needing any secondary modification of proline residues in the Yaa position to hydroxyproline, a characteristic feature of animal collagens. Hydroxyproline can, however, be introduced into recombinant bacterial collagen by co-translational incorporation during fermentation. However, this does not lead to full incorporation and introduces the hydroxyproline into both the Xaa and Yaa positions. It was suggested that the poor solubility of bacterial collagen samples with higher levels of incorporation of hydroxyproline could be due to an increase in protein association at neutral pH. In the present study, cryo-transmission electron microscopy was used to examine the nature and extent of any associations arising from hydroxyproline incorporation. This was examined further, using 2 smaller fragments, where the proline sites are predominantly in either the Xaa position or Yaa position. The present data confirm the importance of the presence of hydroxyproline in assisting in the association between collagen molecules.
先前已描述了多种细菌胶原蛋白样蛋白，它们具有三螺旋的（甘氨酸-任意氨基酸-任意氨基酸）重复结构。它们很稳定，无需将Yaa位置的脯氨酸残基进行任何二级修饰转化为羟脯氨酸，而这是动物胶原蛋白的一个特征。然而，在发酵过程中通过共翻译掺入，可以将羟脯氨酸引入重组细菌胶原蛋白中。然而，这并不会导致完全掺入，并且会将羟脯氨酸同时引入Xaa和Yaa位置。有人提出，羟脯氨酸掺入水平较高的细菌胶原蛋白样品溶解度较差，可能是由于中性pH下蛋白质缔合增加所致。在本研究中，使用冷冻透射电子显微镜来检查由羟脯氨酸掺入引起的任何缔合的性质和程度。使用2个较小的片段进一步对此进行了研究，其中脯氨酸位点主要位于Xaa位置或Yaa位置。目前的数据证实了羟脯氨酸在协助胶原蛋白分子之间缔合方面的重要性。
