Interplay of Electrostatics and Hydrophobic Effects in the Metamorphic Protein Human Lymphotactin. J Phys Chem B 2015 Jul 30;119(30):9547-58
Date
07/03/2015Pubmed ID
26134347DOI
10.1021/acs.jpcb.5b02810Scopus ID
2-s2.0-84938282399 (requires institutional sign-in at Scopus site) 3 CitationsAbstract
The human lymphotactin (hLtn) is a protein that features two native states both of which are physiologically relevant: it is a monomer (hLtn10) at 10 °C with 200 mM salt and a dimer (hLtn40) at 40 °C and without salt. Here we focus on the networks of electrostatic and hydrophobic interactions that display substantial changes upon the conversion from hLtn10 to hLtn40 since they are expected to modulate the relative stability of the two folds. In addition to the Arg 23-Arg 43 interaction discussed in previous work, we find several other like-charge pairs that are likely important to the stability of hLtn10. Free energy perturbation calculations are carried out to explicitly evaluate the contribution of the Arg 23-Arg 43 interaction to the hLtn10 stability. hLtn40 features a larger number of salt bridges, and a set of hydrophobic residues undergo major changes in the solvent accessible surface area between hLtn10 and hLtn40, pointing to their importance to the relative stability of the two folds. We also discuss the use of explicit and implicit solvent simulations for characterizing the conformational ensembles under different solution conditions.
Author List
Korkmaz EN, Volkman BF, Cui QAuthor
Brian F. Volkman PhD Professor in the Biochemistry department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
HumansHydrophobic and Hydrophilic Interactions
Lymphokines
Molecular Dynamics Simulation
Protein Stability
Protein Structure, Secondary
Sialoglycoproteins
Static Electricity
Thermodynamics
