RT Journal Article SR Electronic T1 Nitric oxide sensing by chlorophyll a JF bioRxiv FD Cold Spring Harbor Laboratory SP 146563 DO 10.1101/146563 A1 Abhishek Bhattacharya A1 Pranjal Biswas A1 Puranjoy Kar A1 Piya Roychoudhury A1 Sankar Basu A1 Sanjay Ghosh A1 Kaustab Panda A1 Ruma Pal A1 Anjan Kr. Dasgupta YR 2017 UL http://biorxiv.org/content/early/2017/06/06/146563.abstract AB Nitric oxide (NO) acts as a signalling molecule that has direct and indirect regulatory roles in various functional processes in biology, though in plant kingdom its role is relatively unexplored. One reason for this is the fact that sensing of NO is always challenging. There are very few probes that can classify the different NO species. The present paper proposes a simple but straightforward way for sensing different NO species using chlorophyll, the source of inspiration being hemoglobin that serves as a NO sink in most mamalian system. The proposed method is able to classify NO from DETA-NONOate or (Z)-1-[N-(2-aminoethyl)-N-(2-ammonioethyl) amino] diazen-1-ium-1,2-diolate, nitrite, nitrate and S-nitrosothiol or SNO. This discrimination is carried out by chlorophyll a (chl a) at nano molar (nM) order of sensitivity and at 293K to 310K. Molecular docking reveals the differential binding behaviour of NO and SNO with chlorophyll, the predicted binding affinity matching with the experimental observation. Additional expreiments with diverse range of cyanobacteria reveals that apart from spectroscopic approach the proposed sensing module can be used in microscopic inspection of NO speices. Binding of NO is sensitive to tempertaure and static magnetic field. This provides additional support to the involvement of the porphyrin ring structure to the NO sensing process. This also broadens the scope of the sensing methods as hinted in the text.