Small-angle neutron scattering studies suggest the mechanism of BinAB protein internalization
| Autor: | Mahima Sharma, Vinod K. Aswal, Vinay Kumar, R. Chidambaram |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: | |
| Zdroj: | IUCrJ, Vol 7, Iss 2, Pp 166-172 (2020) |
| Druh dokumentu: | article |
| ISSN: | 2052-2525 20522525 |
| DOI: | 10.1107/S2052252519017159 |
| Popis: | Small-angle neutron scattering (SANS) is one of the most widely used neutron-based approaches to study the solution structure of biological macromolecular systems. The selective deuterium labelling of different protein components of a complex provides a means to probe conformational changes in multiprotein complexes. The Lysinibacillus sphaericus mosquito-larvicidal BinAB proteins exert toxicity through interaction with the receptor Cqm1 protein; however, the nature of the complex is not known. Rationally engineered deuterated BinB (dBinB) protein from the L. sphaericus ISPC-8 species was synthesized using an Escherichia coli-based protein-expression system in M9 medium in D2O for `contrast-matched' SANS experiments. SANS data were independently analysed by ab initio indirect Fourier transform-based modelling and using crystal structures. These studies confirm the dimeric status of Cqm1 in 100% D2O with a longest intramolecular vector (Dmax) of ∼94 Å and a radius of gyration (Rg) of ∼31 Å. Notably, BinB binds to Cqm1, forming a heterodimeric complex (Dmax of ∼129 Å and Rg of ∼40 Å) and alters its oligomeric status from a dimer to a monomer, as confirmed by matched-out Cqm1–dBinB (Dmax of ∼70 Å and Rg of ∼22 Å). The present study thus provides the first insight into the events involved in the internalization of larvicidal proteins, likely by raft-dependent endocytosis. |
| Databáze: | Directory of Open Access Journals |
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