Non-native fold of the putative VPS39 zinc finger domain

Wellcome Open Research

article

Benjamin G. Butt¹  Edward J. Scourfield¹  Stephen C. Graham¹ 

[1] Department of Pathology, University of Cambridge

关键词: CORVET;    membrane trafficking;    zinc finger domain;    class C core;   

DOI  :  10.12688/wellcomeopenres.16078.2

学科分类：内科医学

来源: Wellcome

【 摘 要 】

Background: The multi-subunit homotypic fusion and vacuole protein sorting (HOPS) membrane-tethering complex is involved in regulating the fusion of late endosomes and autophagosomes with lysosomes in eukaryotes. The C-terminal regions of several HOPS components have been shown to be required for correct complex assembly, including the C-terminal really interesting new gene (RING) zinc finger domains of HOPS components VPS18 and VPS41. We sought to structurally characterise the putative C-terminal zinc finger domain of VPS39, which we hypothesised may be important for binding of VPS39 to cellular partners or to other HOPS components.Methods: We recombinantly expressed, purified and solved the crystal structure of the proposed zinc-binding region of VPS39.Results: In the structure, this region forms an anti-parallel β-hairpin that is incorporated into a homotetrameric eight-stranded β-barrel. However, the fold is stabilised by coordination of zinc ions by residues from the purification tag and an intramolecular disulphide bond between two predicted zinc ligands.Conclusions: We solved the structure of the VPS39 C-terminal domain adopting a non-native fold. Our work highlights the risk of non-native folds when purifying small zinc-containing domains with hexahistidine tags. However, the non-native structure we observe may have implications for rational protein design.

【 授权许可】

CC BY