Retardation of the unfolding process by single N-glycosylation of ribonuclease A based on molecular dynamics simulations.
The conformational characteristics of glycosylated- and unglycosylated bovine pancreatic ribonuclease A (RNaseA) were traced with unfolding molecular dynamics simulations using CHARMM program at 470 K. The glycosylated RNase (Glc_RNase) possesses nearly identical protein structure with RNaseA, differing only by presence of a single acetylglucosamine residue N-linked to Asn34 in the RNaseA. Attaching of monomeric N-acetylglucosamine residue to the Asn34 in RNaseA resulted in a change of denaturing process of Glc_RNase. Simulations showed that the unfolding of RNaseA involved significant weakening of nonlocal interactions whereas the glycosylation led Glc_RNase to preserve the nonlocal interactions even in its denatured form. Even in simulations over 8 ns at 470 K, Glc_RNase remained relatively stable as a less denatured conformation. However, conformation of RNaseA was changed to a fully unfolded state before 3 ns of the simulations at 470 K. This difference was due to fact that formation of hydrogen bond bridges and nonlocal contacts induced by the attached N-acetylglucosamine of Glc_RNase showing in the unfolding simulations. These high-temperature unfolding MD simulations provided a theoretical basis for the previous experimental work in which Glc_RNase showed slower unfolding kinetics compared with unglycosylated RNaseA, suggesting that single N-glycosylation induced retardation of unfolding process of the ribonuclease protein.
Choi
Youngjin
Y
Bio/Molecular Informatics Center, Konkuk University, Seoul 143-701, Republic of Korea.
Lee
Jong Hyun
JH
Hwang
Suntae
S
Kim
Joong-Kwon
JK
Jeong
Karpjoo
K
Jung
Seunho
S
D000818:Animals; D002417:Cattle; D019295:Computational Biology / Q000379:methods; D003198:Computer Simulation; D006031:Glycosylation; D006358:Hot Temperature; D006860:Hydrogen Bonding; D006863:Hydrogen-Ion Concentration; D008968:Molecular Conformation; D011487:Protein Conformation; D011489:Protein Denaturation; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D012259:Ribonuclease, Pancreatic / Q000737:chemistry*; D012984:Software
D012259:Ribonuclease, Pancreatic