Title

Role of nitric oxide synthase in insect cell radioresistance: an in-silico analysis

Authors

Shubhankar Suman^{1, 2}, Rakesh Kumar Seth² and Sudhir Chandna^1, *

Affiliation

¹Natural Radiation Response Mechanisms Group, Division of Radiation Biosciences, Institute of Nuclear Medicine and Allied Sciences, Brig. S.K. Majumdar Road, Delhi-110054, India; ²Department of Zoology, University of Delhi, Delhi-110007, India

Email

sudhirchandna@yahoo.com; * Corresponding author

Article Type

Hypothesis

Date

received May 23, 2008; revised July 07, 2008; accepted July 20, 2008; published September 02, 2008

Abstract

Previous studies on various insect cell lines have displayed very high radioresistance in Lepidoptera (butterflies and moths) as compared to mammals as well as other orders of Insecta including Diptera. Since NOS is known to modulate cellular radiation sensitivity, we carried out in silico analysis of Lepidopteran NOS and compared its structural and functional features including the sequence homology, predicted tertiary structure, post-translational phosphorylation and intracellular localization with the other species. Our study demonstrates that Lepidopteran NOS, while carrying significant sequence homology with mammalian nNOS, has structural/ functional features that may enhance resistance to radiation and other stress agents. A higher phosphorylation score of Lepidopteran NOS (0.885±0.02 as against 0.694±0.094 of mammalian NOS; predicted using Net Phos 2.0) was observed at many well-conserved phosphorylation sites, which may reduce NOS activation by stress agents including radiation. Further, the primarily cytoplasmic localization of Lepidopteran NOS (score 23 against 10 of mammalian NOS, derived using WoLFPSORT), aided by higher phosphorylation scores as well as sequence-driven cytoplasmic localizing signals, may significantly reduce amplification of extraneous oxidative damage. Based on these findings, we hypothesize that a primarily cytosolic and less responsive NOS could significantly contribute to radioresistance of Lepidopteran insects as well as their cultured cell lines.

Keywords

nitric oxide (NO); nitric oxide synthase (NOS); multiple sequence alignment (MSA);  phosphorylation mapping; phosphorylation score; sub-cellular localization

Citation

Suman et al., Bioinformation 3(1): 8-13 (2008)

Edited by

P. Kangueane

ISSN

0973-2063

Publisher

Biomedical Informatics

License

This is an Open Access article which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. This is distributed under the terms of the Creative Commons Attribution License.