Structural insight into the unique conformation of cystathionine β-synthase from Toxoplasma gondii

DOI: 10.1016/j.csbj.2021.05.052

Authors: Carmen Fernandez-Rodriguez (Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA)) , Iker Oyenarte (Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA)) , Carolina Conter (University of Verona) , Irene Gonzalez-Recio (Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA)) , Reyes Núñez-Franco (Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA)) , Claudia Gil-Pitarch (Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA)) , Iban Quintana (TEKNIKER, Basque Research and Technology Alliance (BRTA)) , Gonzalo Jiménez-Osés (Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA)) , Paola Dominici (University of Verona) , Maria Luz Martinez-Chantar (Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA)) , Alessandra Astegno (University of Verona) , Luis Alfonso Martinez-Cruz (Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA))
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Computational And Structural Biotechnology Journal , VOL 19 , PAGES 3542 - 3555

State: Published (Approved)
Published: August 2021
Diamond Proposal Number(s): 28360

Abstract: Cysteine plays a major role in the redox homeostasis and antioxidative defense mechanisms of many parasites of the phylum Apicomplexa. Of relevance to human health is Toxoplasma gondii, the causative agent of toxoplasmosis. A major route of cysteine biosynthesis in this parasite is the reverse transsulfuration pathway involving two key enzymes cystathionine β-synthase (CBS) and cystathionine γ-lyase (CGL). CBS from T. gondii (TgCBS) catalyzes the pyridoxal-5́-phosphate-dependent condensation of homocysteine with either serine or O-acetylserine to produce cystathionine. The enzyme can perform alternative reactions that use homocysteine and cysteine as substrates leading to the endogenous biosynthesis of hydrogen sulfide, another key element in maintaining the intracellular redox equilibrium. In contrast with human CBS, TgCBS lacks the N-terminal heme binding domain and is not responsive to S-adenosylmethionine. Herein, we describe the structure of a TgCBS construct that lacks amino acid residues 466-491 and shows the same activity of the native protein. TgCBS Δ466-491 was determined alone and in complex with reaction intermediates. A complementary molecular dynamics analysis revealed a unique domain organization, similar to the pathogenic mutant D444N of human CBS. Our data provides one missing piece in the structural diversity of CBSs by revealing the so far unknown three-dimensional arrangement of the CBS-type of Apicomplexa. This domain distribution is also detected in yeast and bacteria like Pseudomonas aeruginosa. These results pave the way for understanding the mechanisms by which TgCBS regulates the intracellular redox of the parasite, and have far-reaching consequences for the functional understanding of CBSs with similar domain distribution.

Journal Keywords: Toxoplasmosis; Toxoplasma gondii; Reverse transsulfuration; Cystathionine β-synthase; Hydrogen sulfide; Homocysteine; Pyridoxal-5′-phosphate; Crystallography; Bateman module

Diamond Keywords: Toxoplasmosis

Subject Areas: Biology and Bio-materials, Chemistry


Instruments: I03-Macromolecular Crystallography , I24-Microfocus Macromolecular Crystallography

Other Facilities: XALOC at ALBA

Added On: 09/08/2021 14:34

Documents:
1-s2.0-S2001037021002403-main.pdf

Discipline Tags:

Infectious Diseases Health & Wellbeing Biochemistry Chemistry Structural biology Life Sciences & Biotech Parasitology

Technical Tags:

Diffraction Macromolecular Crystallography (MX)