Myosin binding protein C (MyBP-C) is a thick filament involved in the regulation of muscle contraction. Mutations gene for MyBP-C are second most frequent cause hypertrophic cardiomyopathy. binds to myosin with two sites, one at its C-terminus and another N-terminus. The N-terminal site, consisting immunoglobulin domains C1 C2 connected by flexible linker, interacts S2 segment phosphorylation-regulated manner. It assumed that function act as tether fixes S1 heads resting position...

Myosin-binding protein C (MyBP-C) binds to myosin with two binding sites, one close the N terminus and other at terminus. Here we present solution structure of part N-terminal site, third immunoglobulin domain cardiac isoform human MyBP-C (cC2) together a model its interaction myosin. Domain cC2 has beta-sandwich expected from member fold. The C-terminal is very closely related telokin, fragment light chain kinase. also contains cysteines on neighboring strands F G, which would be able form...

Gram-negative bacteria such as E. coli use tripartite efflux pumps AcrAB-TolC to expel antibiotics and noxious compounds. A key feature of the inner membrane transporter component, AcrB, is a short stretch residues known gate/switch loop that divides proximal distal substrate binding pockets. Amino acid substitutions gate are decrease antibiotic resistance conferred by AcrB. Here we present two new AcrB variants, first stripped its bulky side chains, second in which removed entirely. By...

Calmodulin and other members of the EF-hand protein family are known to undergo major changes in conformation upon binding Ca(2+). However, some proteins, such as calbindin D9k, bind Ca(2+) without a significant change conformation. Here, we show importance precise balance solvation energetics conformational change, using mutational analysis partially buried polar groups N-terminal domain calmodulin (N-cam). Several variants were characterized fluorescence, circular dichroism, NMR...

Thiomandelic acid is a simple, broad spectrum, and reasonably potent inhibitor of metallo-beta-lactamases, enzymes that mediate resistance to beta-lactam antibiotics. We report studies by NMR perturbed angular correlation (PAC) spectroscopy the mode binding R S enantiomers thiomandelic acid, focusing on their interaction with two metal ions in cadmium-substituted Bacillus cereus metallo-beta-lactamase. The 113Cd resonances are specifically assigned metals individual sites protein using...

Periplasmic adaptor proteins are essential components of bacterial tripartite multidrug efflux pumps. Here we report the 2.35 Å resolution crystal structure BesA from spirochete Borrelia burgdorferi solved using selenomethionine derivatized protein. shows archetypal linear, flexible, multi‐domain architecture evident among proteobacteria and retains lipoyl, β‐barrel membrane‐proximal domains that interact with periplasmic inner membrane transporter. However, it lacks α‐hairpin domain shown...

Abstract Time‐resolved fluorescence study of single tryptophan‐containing proteins, nuclease, ribonuclease T1, protein G, glucagon, and mastoparan, has been carried out. Three different methods were used for the analysis decays: iterative reconvolution method, as reviewed developed in our laboratory, maximum entropy recent method that we called “energy transfer” method. All proteins show heterogeneous kinetics (multiexponential decay). The origin this heterogeneity is interpreted terms...

Abstract SH2 domains provide fundamental recognition sites in tyrosine kinase‐mediated signaling pathways which, when aberrant, give rise to disease states such as cancer, diabetes, and immune deficiency. Designing specific inhibitors that target the domain‐binding site, however, have presented a major challenge. Despite well over decade of intensive research, clinically useful domain yet become available. A better understanding structural, dynamic, thermodynamic contributions ligand binding...

Proteins within the EF-hand protein family exhibit different conformational responses to Ca2+ binding. Calmodulin and other members of undergo major changes in conformation upon binding Ca2+. However, some proteins, such as calbindin D9k (Clb), bind without a significant change conformation. Here, we investigate effects replacement leucine at position 39 N-terminal domain calmodulin (N-Cam) with phenylalanine derived from Clb. This variant is studied alone context mutations that affect...

The multifunctional protein, beta-catenin, has essential roles in cell adhesion and, through the Wnt signaling pathway, controlling differentiation, development, and generation of cancer. Could distinct molecular forms beta-catenin underlie these two functions? Our single-molecule force spectroscopy armadillo with dynamics (MD) simulation, suggests a model which generates various equilibrium. We find transcriptional factor Tcf4 form complexes different affinities. Specific cellular response...

SH3 domains are common structure, interaction, and regulation modules found in more than 200 human proteins. In this report, we studied the third domain from CIN85 adaptor protein, which plays an important role both receptor tyrosine kinase downregulation phosphatidylinositol 3 inhibition. The structure of includes additional 90° kink after last canonical β-strand features unusual interactions between termini well outside boundaries standard definition. extended portions well-structured held...

Ms1 (also known as STARS and ABRA) has been shown to act an early stress response gene in processes different hypertrophy skeletal cardiac muscle growth of collateral blood vessels. It is important for development zebrafish upregulated mouse models well human failing hearts. possesses actin binding sites at its C-terminus usually found the cell bound filaments cytosol or sarcomeres. We determined NMR structure only folded domain comprising second site called 2 (ABD2, residues 294-375), that...

In Escherichia coli AcrB is a major multidrug exporter, which confers the bacterium resistance to many antibiotics with diverse structural and chemical proprieties. Studies have identified three possible tunnels (or channels) within that different substrates use before reaching distal pocket, from they are subsequently extruded. Recently, we reported mutations in gate loop may affect conformational change kinetics involved substrate export rather than directly affecting molecular...