Assuntos
Acetonitrilas/química , Insulina Regular Humana/química , Proteínas Recombinantes/química , Água/química , Humanos , Ligação de Hidrogênio , Insulina Regular Humana/metabolismo , Modelos Moleculares , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/metabolismo , Engenharia de Proteínas , Subunidades Proteicas , Proteínas Recombinantes/metabolismoRESUMO
A tertiary structure of recombinant A22(G)-B31(K)-B32(R)-human insulin monomer (insulin GKR) has been characterized by (1)H, (13)C NMR at natural isotopic abundance using NOESY, TOCSY, (1)H/(13)C-GHSQC, and (1)H/(13)C-GHSQC-TOCSY spectra. Translational diffusion studies indicate the monomer structure in water/acetonitrile (65/35vol.%). CSI analysis confirms existence of secondary structure motifs present in human insulin standard (HIS). Both techniques allow to establish that in this solvent recombinant insulin GKR exists as a monomer. Starting from structures calculated by the program CYANA, two different refinement protocols used molecular dynamics simulated annealing with the program AMBER; in vacuum (AMBER_VC), and including a generalized Born solvent model (AMBER_GB). From these calculations an ensemble of 20 structures of lowest energy was chosen which represents the tertiary structure of studied insulin. Here we present novel insulin with added A22(G) amino acid which interacts with ß-turn environment resulting in high flexibility of B chain C-terminus.