Backbone dynamics of a symmetric calmodulin dimer in complex with the calmodulin-binding domain of the basic-helix-loop-helix transcription factor SEF2-1/E2-2: a highly dynamic complex.

ABSTRACT: Calmodulin (CaM) interacts specifically as a dimer with some dimeric basic-Helix-Loop-Helix (bHLH) transcription factors via a novel high affinity binding mode. Here we report a study of the backbone dynamics by (15)N-spin relaxation on the CaM dimer in complex with a dimeric peptide that mimics the CaM binding region of the bHLH transcription factor SEF2-1. The relaxation data were measured at multiple magnetic fields, and analyzed in a model-free manner using in-house written software designed to detect nanosecond internal motion. Besides picosecond motions, all residues also experience internal motion with an effective correlation time of approximately 2.5 ns with squared order parameter (S(2)) of approximately 0.75. Hydrodynamic calculations suggest that this can be attributed to motio

SUBMITTER: Larsson G 

PROVIDER: S-EPMC1366606 | biostudies-literature | 2005 Aug

REPOSITORIES: biostudies-literature