Title

Do N-glycoproteins have preference for specific sequons?

Authors

R Shyama Prasad Rao^{1, 2, *}, Bernd Wollenweber¹

Affiliation

¹Aarhus University, Department of Genetics and Biotechnology, Forsøgsvej 1, Slagelse 4200, Denmark; ² Present address: CH20, 3rd cross, 7th main, Saraswathipuram, Mysore 570009, India
 

Email

drrsprao@yahoo.co.in, rao@agrsci.dk

+91 9482546064; *Corresponding author

Article Type

Hypothesis

Date

Received May 31, 2010; Accepted October 13, 2010; Published November 1, 2010
 

Protein N-glycosylation requires the presence of asparagine (N) in the consensus tri-peptide NXS/T (where X is any amino acid, S is serine and T is threonine). Several factors affect the glycosylation potential of NXS/T sequons and one such factor is the type of amino acid at position X. While proline was shown to negatively affect N-glycosylation, the nature of other amino acids at this position is not clear. Using Markov chain analysis of tri-peptide NXS/T from viral, archaeal and eukaryotic proteins as well as experimentally confirmed N-glycosylated sequons from eukaryotic proteins, we show here that the occurrence of most sequon types differ significantly from the expected probability. Sequon types with F, G, I, S, T and V amino acids are consistently preferred while those with P and charged amino acids are under-represented in all four groups. Further, proteins contained far fewer number of possible sequon types (maximum 20 types for NXS or NXT taken separately) for any given number of sequons, which may be explained based on random sampling. Consistent with the present finding, majority of the over-represented sequons found in two important viral envelope glycoproteins (hemagglutinin of influenza A H3N2 and glycoprotein120 of HIV-1) are indeed preferred sequon types, which may provide a selective advantage. Accordingly, although there seems to be some preference for sequons, this preference may not be unique to N-glycosylation.
 

Keywords

HIV, Influenza, N-glycoproteins, Probability, Sequons.

Citation

Rao et al. Bioinformation, 5 (5) 208-212, 2010

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.