title: βB1-crystallin: thermodynamic profiles of molecular interactions.
abstract: BACKGROUND
  β-Crystallins are structural proteins maintaining eye lens transparency and opacification. Previous work demonstrated that dimerization of both βA3 and βB2 crystallins (βA3 and βB2) involves endothermic enthalpy of association (∼8 kcal/mol) mediated by hydrophobic interactions.
  
  
  RESULTS
  Thermodynamic profiles of the associations of dimeric βA3 and βB1 and tetrameric βB1/βA3 were measured using sedimentation equilibrium. The homo- and heteromolecular associations of βB1 crystallin are dominated by exothermic enthalpy (-13.3 and -24.5 kcal/mol, respectively).
  
  
  CONCLUSIONS
  Global thermodynamics of βB1 interactions suggest a role in the formation of stable protein complexes in the lens via specific van der Waals contacts, hydrogen bonds and salt bridges whereas those β-crystallins which associate by predominately hydrophobic forces participate in a weaker protein associations.
authors.affiliation: National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Monika B
authors.initials: MB
authors.lastname: Dolinska
authors.forename: Paul T
authors.initials: PT
authors.lastname: Wingfield
authors.forename: Yuri V
authors.initials: YV
authors.lastname: Sergeev
mesh_terms: D000818:Animals; D004734:Energy Metabolism; D006801:Humans; D051379:Mice; D008954:Models, Biological; D008958:Models, Molecular; D011485:Protein Binding / Q000502:physiology; D055503:Protein Multimerization / Q000502:physiology*; D020836:Protein Structure, Quaternary; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D013696:Temperature; D013816:Thermodynamics; D038205:beta-Crystallin A Chain / Q000737:chemistry / Q000378:metabolism; D038206:beta-Crystallin B Chain / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D011994:Recombinant Proteins; D038205:beta-Crystallin A Chain; D038206:beta-Crystallin B Chain