bioRxiv preprint doi: https://doi.org/10.1101/683490; this version posted June 27, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. Two pathways for thiosulfate oxidation in the alphaproteobacterial chemolithotroph Paracoccus thiocyanatus SST Moidu Jameela Rameez1, Prosenjit Pyne1,$, Subhrangshu Mandal1, Sumit Chatterjee1, Masrure 5 Alam1,#, Sabyasachi Bhattacharya1, Nibendu Mondal1, Jagannath Sarkar1 and Wriddhiman Ghosh1* Addresses: Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata 700054, India. 10 Present address: $National Institute of Cholera and Enteric Diseases, P-33, C. I. T Road, Scheme XM, Beliaghata, Kolkata 700 010, India. #Department of Biological Sciences, Aliah University, IIA/27, New Town, Kolkata-700160, India. *Correspondence:
[email protected] 15 Running title: Thiosulfate oxidation via tetrathionate in an alphaproteobacterium Keywords: sulfur-chemolithotrophy, Sox multienzyme system, Alphaproteobacteria, thiosulfate oxidation via tetrathionate-intermediate, thiosulfate 20 dehydrogenase, tetrathionate oxidation Abstract Chemolithotrophic bacteria oxidize various sulfur species for energy and electrons, thereby 25 operationalizing biogeochemical sulfur cycles in nature. The best-studied pathway of bacterial sulfur-chemolithotrophy, involving direct oxidation of thiosulfate to sulfate (without any free intermediate) by the SoxXAYZBCD multienzyme system, is apparently the exclusive