title: Backbone dynamics of the 8 kDa dynein light chain dimer reveals molecular basis of the protein's functional diversity.
abstract: Axonemal and cytoplasmic dyneins share a highly conserved 8 kDa light chain (DLC8) for motor assembly and function. Other than serving as a light chain of dynein complexes, DLC8 has been shown to bind a larger number of proteins with diverse biological functions including cell cycle control, apoptosis, and cell polarity maintenance. Therefore, DLC8 is likely a multifunctional regulatory protein. DLC8 exists as a dimer in solution, and the protein dimer is capable of binding to two target molecules. In this work, the backbone dynamics of DLC8, both in its apo- and target-peptide bound forms, were characterized by 15N NMR relaxation studies. The relaxation data were analyzed using model-free approach. We show that the target peptide-binding region of apo-DLC8 experiences microsecond-to-millisecond time scale conformational fluctuation, suggesting that the target-binding region of the protein is capable of adjusting its shape and size in responding to its various targets. The conformational breathing of the target-binding region of apo-DLC8 was also supported by backbone amide exchange experiment. Such segmental conformational motion of the protein is significantly reduced upon forming a complex with a target peptide. The dynamic properties of DLC8 in solution provide insight into the protein's diverse sequence-dependent target binding.
authors.affiliation: Department of Biochemistry, The Hong Kong University of Science and Technology, Kowloon, PR China.
authors.forename: Jing-Song
authors.initials: JS
authors.lastname: Fan
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhang
authors.forename: Hidehito
authors.initials: H
authors.lastname: Tochio
authors.forename: Mingjie
authors.initials: M
authors.lastname: Zhang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001059:Apoproteins / Q000737:chemistry / Q000378:metabolism; D051017:Apoptosis Regulatory Proteins; D000072224:Bcl-2-Like Protein 11; D002352:Carrier Proteins / Q000378:metabolism; D056445:Cytoplasmic Dyneins; D019281:Dimerization; D004398:Dyneins / Q000737:chemistry* / Q000378:metabolism*; D008565:Membrane Proteins; D008958:Models, Molecular; D008970:Molecular Weight; D019906:Nuclear Magnetic Resonance, Biomolecular; D010455:Peptides / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D011518:Proto-Oncogene Proteins; D051381:Rats; D013329:Structure-Activity Relationship; D013379:Substrate Specificity
chemical_list: D001059:Apoproteins; D051017:Apoptosis Regulatory Proteins; D000072224:Bcl-2-Like Protein 11; C000606778:Bcl2l11 protein, rat; D002352:Carrier Proteins; D008565:Membrane Proteins; D010455:Peptides; D011518:Proto-Oncogene Proteins; C486069:Dynll1 protein, rat; D056445:Cytoplasmic Dyneins; D004398:Dyneins