title: Small-angle neutron scattering study of protein crowding in liquid and solid phases: lysozyme in aqueous solution, frozen solution, and carbohydrate powders.
abstract: The structure, interactions, and interprotein configurations of the protein lysozyme were studied in a variety of phases. These properties have been studied under a variety of solution conditions before, during, and after freezing and after freeze-drying in the presence of glucose and trehalose. Contrast variation experiments have also been performed to determine which features of the scattering in the frozen solutions are from the protein and which are from the ice structure. Data from lysozyme at concentrations ranging from 1 to 100 mg/mL in solution and water ice with NaCl concentrations ranging from 0 to 0.4 mol/L are fit to model small-angle neutron scattering (SANS) intensity functions consisting of an ellipsoidal form factor and either a screened-Coulomb or hard-sphere structure factor. Parameters such as protein volume fraction and long dimension are followed as a function of temperature and salt concentration. The SANS results are compared to real space models of concentrated lysozyme solutions at the same volume fractions obtained from Monte Carlo simulations. A cartoon representation of the frozen lysozyme solution in 0 mol/L NaCl is presented based on the SANS and Monte Carlo results, along with those obtained from other complementary methods.
authors: NIST Center for Neutron Research, National Institute of Standards and Technology, 100 Bureau Drive, Mail Stop 6102, Gaithersburg, Maryland 20899-6102, United States. joseph.curtis@nist.gov
authors: Joseph E
authors: JE
authors: Curtis
authors: Hirsh
authors: H
authors: Nanda
authors: Sheila
authors: S
authors: Khodadadi
authors: Marcus
authors: M
authors: Cicerone
authors: Hyo Jin
authors: HJ
authors: Lee
authors: Arnold
authors: A
authors: McAuley
authors: Susan
authors: S
authors: Krueger
mesh_terms: D020816:Amino Acid Motifs; D002241:Carbohydrates / Q000737:chemistry*; D007053:Ice; D009113:Muramidase / Q000737:chemistry*; D044367:Phase Transition; D011208:Powders / Q000737:chemistry*; D011506:Proteins / Q000737:chemistry; D053838:Scattering, Small Angle; D014867:Water / Q000737:chemistry*
chemical_list: D002241:Carbohydrates; D007053:Ice; D011208:Powders; D011506:Proteins; D014867:Water; D009113:Muramidase