title: In silico design and analysis of a new hyperglycosylated analog of erythropoietin to improve drug efficacy.
abstract: BACKGROUND
  The enhancement of glycosylation by applying glycoengineering approaches has become widely used to boost properties for protein therapeutics. The objective of this work was to engineer a new hyperglycosylated analog of erythropoietin (EPO) with appropriately targeted N-linked carbohydrates through bioinformatics tools.
  
  
  METHODS
  The EPO protein sequence was retrieved from NCBI protein sequence database. Prediction of N-glycosylation sites for the target protein was done using the prediction server, NetNGlyc. The three-dimensional model of glycoengineered EPO (named as kypoetin) was constructed using the homology modeling program. Ramchandran plot obtained from PROCHECK server was used to check stereochemical property. Meanwhile, 3D model of kypoetin with attached N-carbohydrates was built up using the GlyProt server.
  
  
  RESULTS
  In the new modified analog, three additional N-glycosylation sites at amino-acid positions 30, 34 and 86 were inserted. Ramchandran plot analysis showed 81.6% of the residues in the most favored region, 15.6% in the additional allowed, 1.4% in the generously allowed regions and 1.4% in the disallowed region. 3D structural modeling showed that attached carbohydrates were on the proper spatial position. The whole solvent accessible surface areas of kypoetin (15132.69) were higher than EPO (9938.62).
  
  
  CONCLUSIONS
  Totally, various model evaluation methods indicated that the glycoengineered version of EPO had considerably good geometry and acceptable profiles for clinical studies and could be considered as the effective drug.
authors: Biochemistry Department, Genetic and Metabolism Research Group, Pasteur Institute of Iran, Tehran ; Department of Medical Biotechnology, School of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran.
authors: Anvarsadat
authors: A
authors: Kianmehr
authors: Biochemistry Department, Genetic and Metabolism Research Group, Pasteur Institute of Iran, Tehran.
authors: Hamid Shahbaz
authors: HS
authors: Mohammadi
authors: National Cell Bank of Iran, New Technologies Research Group, Pasteur Institute of Iran, Tehran, Iran.
authors: Mohammad Ali
authors: MA
authors: Shokrgozar
authors: Biochemistry Department, Genetic and Metabolism Research Group, Pasteur Institute of Iran, Tehran.
authors: Eskandar
authors: E
authors: Omidinia
keywords: Erythropoietin (EPO); glycoengineering; in silico