title: Placement of 19F into the center of GB1: effects on structure and stability.
abstract: A structural and thermodynamic characterization of 5F-Trp-substituted immunoglobulin binding domain B1 of streptococcal protein G (GB1) was carried out by nuclear magnetic resonance and circular dichroism spectroscopy. A single fluorine reporter atom was positioned at the center of the three-dimensional structure, uniquely poised to be exploited for studying interior properties of this protein. We demonstrate that the introduction of 5F-Trp does not affect the global and local architecture of GB1 and has no influence on the thermodynamic stability. The favorable properties of the fluorinated GB1 render this molecule a desirable model system for the development of spectroscopic methodology and theoretical calculations.
authors.affiliation: Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Building 5, Room 130, Bethesda, MD 20892, USA.
authors.forename: Ramón
authors.initials: R
authors.lastname: Campos-Olivas
authors.forename: Rehan
authors.initials: R
authors.lastname: Aziz
authors.forename: Gregory L
authors.initials: GL
authors.lastname: Helms
authors.forename: Jeremy N S
authors.initials: JN
authors.lastname: Evans
authors.forename: Angela M
authors.initials: AM
authors.lastname: Gronenborn
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D002942:Circular Dichroism; D005461:Fluorine / Q000737:chemistry*; D006439:Hemodynamics; D007074:Immunoglobulin G / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D016296:Mutagenesis; D009154:Mutation; D011487:Protein Conformation; D011489:Protein Denaturation; D017434:Protein Structure, Tertiary; D013291:Streptococcus / Q000737:chemistry; D013816:Thermodynamics; D014364:Tryptophan / Q000737:chemistry*
chemical_list: D001426:Bacterial Proteins; C034284:IgG Fc-binding protein, Streptococcus; D007074:Immunoglobulin G; D005461:Fluorine; D014364:Tryptophan