Small-angle neutron scattering study of Bence-Jones protein Mcg: comparison of structures in solution and in crystal

Journal Article · Tue Jun 08 00:00:00 EDT 1982 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00541a011· OSTI ID:6933811

Schiffer, M ^[1]; Stevens, F J; Westholm, F A; Kim, S S; Carlson, R D

---

1. Argonne National Lab., IL

Small-angle neutron scattering measurements in dilute solution were performed on the Mcg Bence-Jones protein dimer, for which accurate atomic coordinates have been determined by crystallographic methods. The measured radius of gyration (R/sub g/) in H/sub 2/O buffer is 24.0 +/- 0.4 angstrom and in D/sub 2/O buffer is 23.3 +/- O.1 angstrom; the calculated value of R/sub v/ (R/sub g/ in vacuo) is 24.0 angstrom. On the basis of a match point of 44.2% D/sub 2/O concentration, the experimental partial specific volume is 0.74 cm/sup 3//g. The experimentally derived molecular weight of 47 000 is in very good agreement with that (45 500) calculated from the amino acid composition. For comparisons with different Fab's (antigen binding fragments) exhibiting various ''elbow bends'' due to the flexibility of the switch peptide between variable and constant domains of the immunoglobulin chains, calculation of the R/sub g/ value of the Mcg dimer was performed as a function of the elbow bend. The R/sub g/ varied from 22.8 to 26.0 angstrom as the elbow bend was opened from 100/sup 0/ to 180/sup 0/; the maximum radius of gyration of the particle was 26.5 angstrom with the switch peptide stretched by separating the variable and constant domains by an additional 1.5 angstrom at an elbow bend of 180/sup 0/.

• OSTI ID: 6933811
• Journal Information: Biochemistry; (United States), Vol. 21:12
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
IMMUNOGLOBULINS
STRUCTURAL CHEMICAL ANALYSIS
COMPARATIVE EVALUATIONS
CRYSTAL STRUCTURE
CRYSTALLOGRAPHY
DIMERS
NEUTRON DIFFRACTION
PEPTIDES
SMALL ANGLE SCATTERING
SOLUTIONS
COHERENT SCATTERING
DIFFRACTION
DISPERSIONS
GLOBULINS
MIXTURES
ORGANIC COMPOUNDS
PROTEINS
SCATTERING
550200* - Biochemistry