Evidence for direct squalene and 2,3-oxidosqualene binding by supernatant protein factor

Christen, Monika; Marcaida, Maria; Lamprakis, Christos; Aeschimann, Walter; Vaithilingam, Jathana; Schneider, Petra; Hilbert, Manuel; Schneider, Gisbert; Cascella, Michele; Stocker, Achim (2015). Evidence for direct squalene and 2,3-oxidosqualene binding by supernatant protein factor. Journal of structural biology, 190(190), pp. 261-270. Elsevier 10.1016/j.jsb.2015.05.001

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We present the crystal structures of the SEC14-like domain of supernatant protein factor (SPF) in complex with squalene and 2,3-oxidosqualene. The structures were resolved at 1.75 Å (complex with squalene) and 1.6 Å resolution (complex with 2,3-oxidosqualene), leading in both cases to clear images of the protein/ substrate interactions. Ligand binding is facilitated by removal of the Golgi-dynamics (GOLD) C-terminal domain of SPF, which, as shown in previous structures of the apo-protein, blocked the opening of the binding pocket to the exterior. Both substrates bind into a large hydrophobic cavity, typical of such lipid-transporter family. Our structures report no specific recognition mode for the epoxide group. In fact, for both molecules, ligand affinity is dominated by hydrophobic interactions, and independent investigations by computational models or differential scanning micro-calorimetry reveal similar binding affinities for both ligands. Our findings elucidate the molecular bases of the role of SPF in sterol endo-synthesis, supporting the original hypothesis that SPF is a facilitator of substrate flow within the sterol synthetic pathway. Moreover, our results suggest that the GOLD domain acts as a regulator, as its conformational displacement must occur to favor ligand binding and release during the different synthetic steps.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Departement of Chemistry and Biochemistry
04 Faculty of Medicine > Pre-clinic Human Medicine > Institute of Social and Preventive Medicine

UniBE Contributor:

Marcaida, Maria; Lamprakis, Christos; Aeschimann, Walter; Vaithilingam, Jathana; Cascella, Michele and Stocker, Achim

Subjects:

500 Science > 570 Life sciences; biology
500 Science > 540 Chemistry
600 Technology > 610 Medicine & health
300 Social sciences, sociology & anthropology > 360 Social problems & social services

ISSN:

1047-8477

Publisher:

Elsevier

Language:

English

Submitter:

Achim Stocker

Date Deposited:

09 Nov 2015 15:44

Last Modified:

15 Jan 2017 02:01

Publisher DOI:

10.1016/j.jsb.2015.05.001

BORIS DOI:

10.7892/boris.72540

URI:

https://boris.unibe.ch/id/eprint/72540

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