Völkner Kerstin, Jost Alisa, Pfeifer Felicitas
Microbiology and Archaea, Department of Biology, Technical University of Darmstadt, Darmstadt, Germany.
Front Microbiol. 2020 Nov 12;11:610179. doi: 10.3389/fmicb.2020.610179. eCollection 2020.
forms gas vesicles consisting of a protein wall surrounding a gas-filled space. The hydrophobic 8-kDa protein GvpA is the major constituent of the ribbed wall, stabilized by GvpC at the exterior surface. In addition, eight accessory Gvp proteins are involved, encoded by that are co-transcribed in early stages of growth. Most of these proteins are essential, but their functions are not yet clear. Here we investigate whether GvpF through GvpM interact. Pull-down experiments performed in with the cellulose-binding-domain as tag suggested many interactions, and most of these were supported by the split-GFP analyses. The latter study indicated that GvpL attracted all other accessory Gvp, and the related GvpF bound besides GvpL also GvpG, GvpH and GvpI. A strong interaction was found between GvpH and GvpI. GvpG showed affinity to GvpF and GvpL, whereas GvpJ, GvpK and GvpM bound GvpL only. Using GvpA for similar analyses yielded GvpF as the only interaction partner. The contact site of GvpF was confined to the N-terminal half of GvpA and subsequently mapped to certain amino acids. Taken together, our results support the idea that the accessory Gvp form a complex early in gas-vesicle assembly attracting GvpA GvpF.
形成由围绕充满气体空间的蛋白质壁组成的气体囊泡。疏水的8 kDa蛋白质GvpA是带肋壁的主要成分，在外表面由GvpC稳定。此外，还有八种辅助Gvp蛋白质参与其中，由在生长早期共同转录的基因编码。这些蛋白质中的大多数是必需的，但其功能尚不清楚。在这里，我们研究了GvpF到GvpM是否相互作用。在以纤维素结合结构域为标签的实验中进行的下拉实验表明存在许多相互作用，其中大多数得到了分裂GFP分析的支持。后一项研究表明，GvpL吸引了所有其他辅助Gvp，相关的GvpF除了与GvpL结合外，还与GvpG、GvpH和GvpI结合。发现GvpH和GvpI之间有强烈的相互作用。GvpG对GvpF和GvpL有亲和力，而GvpJ、GvpK和GvpM仅与GvpL结合。使用GvpA进行类似分析得到GvpF是唯一的相互作用伙伴。GvpF的接触位点局限于GvpA的N端一半，随后定位到某些氨基酸。综上所述，我们的结果支持这样一种观点，即辅助Gvp在气体囊泡组装早期形成一个复合物，吸引GvpA和GvpF。
