Changes in the structure of calmodulin induced by a peptide based on the calmodulin-binding domain of myosin light chain kinase

Journal Article · Tue Aug 08 00:00:00 EDT 1989 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00442a032· OSTI ID:5350788

Heidorn, D B; Seeger, P A; Rokop, S E; Blumenthal, D K; Means, A R; Crespi, H; Trewhella, J ^[1]

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1. Los Alamos National Laboratory, NM (USA)

Small-angle X-ray and neutron scattering data were used to study the solution structure of calmodulin complexed with a synthetic peptide corresponding to residues 577-603 of rabbit skeletal muscle myosin light chain kinase. The X-ray data indicate that, in the presence of Ca{sup 2+}, the calmodulin-peptide complex has a structure that is considerably more compact than uncomplexed calmodulin. The radius of gyration, R{sub g}, for the complex is approximately 20% smaller than that of uncomplexed Ca{sup 2+}{center dot}calmodulin, and the maximum dimension, d{sub max}, for the complex is also about 20% smaller. The peptide-induced conformational rearrangement of calmodulin is (Ca{sup 2+}) dependent. The length distribution function for the complex is more symmetric than that for uncomplexed Ca{sup 2+}{center dot}calmodulin, indicating that more of the mass is distributed toward the center of mass for the complex, compared with the dumbbell-shaped Ca{sup 2+}{center dot}calmodulin. The solvent contrast dependence of R{sub g} for neutron scattering indicates that the peptide is located more toward the center of the complex, while the calmodulin is located more peripherally, and that the centers of mass of the calmodulin and the peptide are not coincident. The scattering data support the hypothesis that the interconnecting helix region observed in the crystal structure for calmodulin is quite flexible in solution, allowing the two lobes of calmodulin to form close contacts on binding the peptide. This flexibility of the central helix may play a critical role in activating target enzymes such as myosin light chain kinase.

• OSTI ID: 5350788
• Journal Information: Biochemistry; (USA), Vol. 28:16; ISSN 0006-2960
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
CALMODULIN
CONFORMATIONAL CHANGES
PHOSPHOTRANSFERASES
BIOCHEMICAL REACTION KINETICS
MUSCLES
NEUTRON DIFFRACTION
NEUTRONS
PEPTIDES
X-RAY DIFFRACTION
BARYONS
COHERENT SCATTERING
DIFFRACTION
ELEMENTARY PARTICLES
ENZYMES
FERMIONS
HADRONS
KINETICS
NUCLEONS
ORGANIC COMPOUNDS
PHOSPHORUS-GROUP TRANSFERASES
PROTEINS
REACTION KINETICS
SCATTERING
TRANSFERASES
550602* - Medicine- External Radiation in Diagnostics- (1980-)