Biochemical and structural analysis of a cytosolic sulfotransferase of the malaria vector Anopheles gambiae overexpressed in the reproductive tissues

• Published in: Current research in structural biology 2022-01, Vol.4, p.246-255
• Main Authors: Esposito Verza, Arianna, Miggiano, Riccardo, Lombardo, Fabrizio, Fiorillo, Carmine, Arcà, Bruno, Purghé, Beatrice, Del Grosso, Erika, Galli, Ubaldina, Rizzi, Menico, Rossi, Franca
• Format: Article
• Language: English
• Subjects: Crystal structure; Cytosolic sulfotransferase; Differential mRNA expression; Mosquito; Reproductive system; SULT
• ISSN: 2665-928X; 2665-928X
• DOI: 10.1016/j.crstbi.2022.07.001

The temporary or permanent chemical modification of biomolecules is a crucial aspect in the physiology of all living species. However, while some modules are well characterised also in insects, others did not receive the same attention. This holds true for sulfo-conjugation that is catalysed by cytosolic sulfotransferases (SULT), a central component of the metabolism of endogenous low molecular weight molecules and xenobiotics. In particular, limited information is available about the functional roles of the mosquito predicted enzymes annotated as SULTs in genomic databases. The herein described research is the first example of a biochemical and structural study of a SULT of a mosquito species, in general, and of the malaria vector Anopheles gambiae in particular. We confirmed that the AGAP001425 transcript displays a peculiar expression pattern that is suggestive of a possible involvement in modulating the mosquito reproductive tissues physiology, a fact that could raise attention on the enzyme as a potential target for insect-containment strategies. The crystal structures of the enzyme in alternative ligand-bound states revealed elements distinguishing AgSULT-001425 from other characterized SULTs, including a peculiar conformational plasticity of a discrete region that shields the catalytic cleft and that could play a main role in the dynamics of the reaction and in the substrate selectivity of the enzyme. Along with further in vitro biochemical studies, our structural investigations could provide a framework for the discovery of small-molecule inhibitors to assess the effect of interfering with AgSULT-001425-mediated catalysis at the organismal level. [Display omitted] •Mosquito cytosolic sulfotransferases (SULT) are poorly characterized.•A SULT-encoding gene is highly transcribed in Anopheles male reproductive system.•The corresponding enzyme is a genuine SULT acting on small phenolic molecules.•We solved the AgSULT crystal structure in its substrate-free and ligand-bound states.•The peculiar features of AgSULT could drive the design of isozyme-specific inhibitors.