Specific interactions of the alkali light chain 1 in skeletal myosin heads probed by chemical cross-linking

Biochemistry ◽  
1986 ◽  
Vol 25 (25) ◽  
pp. 8325-8330 ◽  
Author(s):  
Jean Pierre Labbe ◽  
Etienne Audemard ◽  
Raoul Bertrand ◽  
Ridha Kassab
Keyword(s):  
Light Chain ◽  
Cross Linking ◽  
Specific Interactions ◽  
Skeletal Myosin ◽  
Chemical Cross Linking

scholarly journals Addressing the Molecular Mechanism of Longitudinal Lamin Assembly Using Chimeric Fusions

Cells ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1633 ◽  
Author(s):  
Giel Stalmans ◽  
Anastasia V. Lilina ◽  
Pieter-Jan Vermeire ◽  
Jan Fiala ◽  
Petr Novák ◽  
...  
Keyword(s):  
Cell Nucleus ◽  
Molecular Model ◽  
Coiled Coil ◽  
Cross Linking ◽  
Specific Interactions ◽  
Molecular Architecture ◽  
Filament Assembly ◽  
Assembly Mechanism ◽  
Recombinant Fragments ◽  
Chemical Cross Linking

The molecular architecture and assembly mechanism of intermediate filaments have been enigmatic for decades. Among those, lamin filaments are of particular interest due to their universal role in cell nucleus and numerous disease-related mutations. Filament assembly is driven by specific interactions of the elementary dimers, which consist of the central coiled-coil rod domain flanked by non-helical head and tail domains. We aimed to investigate the longitudinal ‘head-to-tail’ interaction of lamin dimers (the so-called ACN interaction), which is crucial for filament assembly. To this end, we prepared a series of recombinant fragments of human lamin A centred around the N- and C-termini of the rod. The fragments were stabilized by fusions to heterologous capping motifs which provide for a correct formation of parallel, in-register coiled-coil dimers. As a result, we established crystal structures of two N-terminal fragments one of which highlights the propensity of the coiled-coil to open up, and one C-terminal rod fragment. Additional studies highlighted the capacity of such N- and C-terminal fragments to form specific complexes in solution, which were further characterized using chemical cross-linking. These data yielded a molecular model of the ACN complex which features a 6.5 nm overlap of the rod ends.

scholarly journals Localization of Calmodulin and Dynein Light Chain Lc8 in Flagellar Radial Spokes

2001 ◽  
Vol 153 (6) ◽  
pp. 1315-1326 ◽  
Author(s):  
Pinfen Yang ◽  
Dennis R. Diener ◽  
Joel L. Rosenbaum ◽  
Winfield S. Sale
Keyword(s):  
Light Chain ◽  
Crucial Role ◽  
Cross Linking ◽  
Dynein Light Chain ◽  
Flagellar Motility ◽  
Radial Spoke ◽  
Size And Shape ◽  
Radial Spokes ◽  
Chemical Cross Linking

Genetic and in vitro analyses have revealed that radial spokes play a crucial role in regulation of ciliary and flagellar motility, including control of waveform. However, the mechanisms of regulation are not understood. Here, we developed a novel procedure to isolate intact radial spokes as a step toward understanding the mechanism by which these complexes regulate dynein activity. The isolated radial spokes sediment as 20S complexes that are the size and shape of radial spokes. Extracted radial spokes rescue radial spoke structure when reconstituted with isolated axonemes derived from the radial spoke mutant pf14. Isolated radial spokes are composed of the 17 previously defined spoke proteins as well as at least five additional proteins including calmodulin and the ubiquitous dynein light chain LC8. Analyses of flagellar mutants and chemical cross-linking studies demonstrated calmodulin and LC8 form a complex located in the radial spoke stalk. We postulate that calmodulin, located in the radial spoke stalk, plays a role in calcium control of flagellar bending.

Statistical Force-Field for Structural Modeling Using Chemical Cross-Linking/mass Spectrometry Distance Constraints

2018 ◽  
Author(s):  
Allan J. R. Ferrari ◽  
Fabio C. Gozzo ◽  
Leandro Martinez
Keyword(s):  
Mass Spectrometry ◽  
Amino Acid ◽  
Force Field ◽  
Protein Structures ◽  
Protein Structure Determination ◽  
Structural Modeling ◽  
Cross Linking ◽  
Amino Acid Residues ◽  
Distance Constraints ◽  
Chemical Cross Linking

<div><p>Chemical cross-linking/Mass Spectrometry (XLMS) is an experimental method to obtain distance constraints between amino acid residues, which can be applied to structural modeling of tertiary and quaternary biomolecular structures. These constraints provide, in principle, only upper limits to the distance between amino acid residues along the surface of the biomolecule. In practice, attempts to use of XLMS constraints for tertiary protein structure determination have not been widely successful. This indicates the need of specifically designed strategies for the representation of these constraints within modeling algorithms. Here, a force-field designed to represent XLMS-derived constraints is proposed. The potential energy functions are obtained by computing, in the database of known protein structures, the probability of satisfaction of a topological cross-linking distance as a function of the Euclidean distance between amino acid residues. The force-field can be easily incorporated into current modeling methods and software. In this work, the force-field was implemented within the Rosetta ab initio relax protocol. We show a significant improvement in the quality of the models obtained relative to current strategies for constraint representation. This force-field contributes to the long-desired goal of obtaining the tertiary structures of proteins using XLMS data. Force-field parameters and usage instructions are freely available at http://m3g.iqm.unicamp.br/topolink/xlff <br></p></div><p></p><p></p>

scholarly journals Structure of cyanobacterial phycobilisome core revealed by structural modeling and chemical cross-linking

2021 ◽  
Vol 7 (2) ◽  
pp. eaba5743
Author(s):  
Haijun Liu ◽  
Mengru M. Zhang ◽  
Daniel A. Weisz ◽  
Ming Cheng ◽  
Himadri B. Pakrasi ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Excitation Energy Transfer ◽  
Energy Coupling ◽  
Regulatory Elements ◽  
Photochemical Activity ◽  
Structural Basis ◽  
Bottom Surface ◽  
Cross Linking ◽  
Orange Carotenoid Protein ◽  
Chemical Cross Linking

In cyanobacteria and red algae, the structural basis dictating efficient excitation energy transfer from the phycobilisome (PBS) antenna complex to the reaction centers remains unclear. The PBS has several peripheral rods and a central core that binds to the thylakoid membrane, allowing energy coupling with photosystem II (PSII) and PSI. Here, we have combined chemical cross-linking mass spectrometry with homology modeling to propose a tricylindrical cyanobacterial PBS core structure. Our model reveals a side-view crossover configuration of the two basal cylinders, consolidating the essential roles of the anchoring domains composed of the ApcE PB loop and ApcD, which facilitate the energy transfer to PSII and PSI, respectively. The uneven bottom surface of the PBS core contrasts with the flat reducing side of PSII. The extra space between two basal cylinders and PSII provides increased accessibility for regulatory elements, e.g., orange carotenoid protein, which are required for modulating photochemical activity.

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