Structure And Evolution Of Calcium-Modulated Protein

Kretsinger, Robert H.; Wasserman, R. H.

doi:10.3109/10409238009105467

Cited by 957 publications

(390 citation statements)

References 219 publications

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“…Vertical arrows point to-in "Materials and Methods." Peak 1 is R1T3 (residues 31-37), peak 2 is wards amino termini of trypsin peptides obtained from subdigests of R1T2 (residues [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30], and peak 3 is RITI (residues 1-13). Composiarginine peptides R I and R5.…”

Section: Resultsmentioning

confidence: 99%

Structural Characterization of a Higher Plant Calmodulin

Lukas

Iverson²,

Schleicher³

et al. 1984

Plant Physiol.

107

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ABSTRACICalmodulin is a eukaryotic calcium binding protein which has several calcium-dependent in vitro activities. Presented in this report is a structural characterization of calmodulin from spinach leaves (Spinacia okracea determine what differences might exist in the primary structure of the plant protein compared to other known calmodulins. Any functional differences must be related to the covalent structure which, in turn, determines the three-dimensional structure. Presented here is amino acid sequence data and homologous alignments which provide a proposed primary structure of spinach calmodulin. Certain portions of the amino acid sequence of spinach calmodulin have appeared elsewhere (3, 27). MATERIALS AND METHODSCalmodulin is a eukaryotic Ca binding protein which modulates the activity of a number ofenzymes in vitro (13). Complete amino acid sequences have been determined for bovine brain (12,27,29) and human brain calmodulin (21). Nearly complete sequences have been published for rabbit skeletal muscle (6), bovine uterus (6), rat testis (4), sea anenome (24), Renilla (10), Tetrahymena (30), and scallop (25)

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Section: Resultsmentioning

confidence: 99%

Structural Characterization of a Higher Plant Calmodulin

Lukas

Iverson²,

Schleicher³

et al. 1984

Plant Physiol.

107

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“…X-ray and NMR structural studies of TnC reveal a dumbbell-shaped molecule with two globular N-and C-terminal domains connected by a central helical linker (13)(14)(15). Each globular domain consists of two EF hand motifs, very homologous and evolutionarily related in the Ca 2+ -binding protein family (16). The EF hand motif is formed by a helix, a 12-residue (rich in D and E) Ca 2+ -binding loop, and second helix.…”

Section: Troponin Cmentioning

confidence: 99%

The Role of Troponins in Muscle Contraction

2002

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SummaryTroponin (Tn) is the sarcomeric Ca 2+ regulator for striated (skeletal and cardiac) muscle contraction. On binding Ca 2+ Tn transmits information via structural changes throughout the actintropomyosin filaments, activating myosin ATPase activity and muscle contraction. Although the Tn-mediated regulation of striated muscle contraction is now well understood, the role of different Tn isoforms in these processes is the subject of intensive investigations. This review addresses the physiological significance of the multiple Tn isoforms in skeletal and cardiac muscles as well as their role in the regulation of contraction.

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“…Thirdly there are the interactions between the new hybrid subunit and the remainder of the protein. The fact that the structures of both the helix-loop-helix EF-hand and the pairs of EF-hands in TnC, calmodulin and parvalbumin are very similar (Kretsinger, 1980;Srtynadka and James, 1989) suggested that it might be possible to transplant an EF-hand as a whole, retaining both the intra-and inter-domain interactions. EFhand domain transplants between skeletal and smooth muscle myosin RLCs have recently been successfully performed to analyse the function of the N-and C-terminal domains in the regulatory function of the RLC molecule (Messer and Kendrick-Jones, 1991).…”

Section: Discussionmentioning

confidence: 99%

“…They all contain four EF-hands, each consisting of a pair of almost perpendicular helices linked by a central metal-binding loop where six negative charges coordinate the metal ligand. Troponin C and calmodulin have four functional metal-binding sites in the EF-hands (Kretsinger, 1980). In calmodulin the four sites have roughly the same specificity and affinity (Crouch and Klee, 1980) whereas TnC possesses two highaffinity sites capable of binding calcium or magnesium and two low-affinity, calcium-specific sites (Potter and Gergely, 1975 site has a high affinity for calcium and magnesium and is considered to be a non-specific binding site (Alexis and Gratzer, 1978 ;Chantler and Szent-Gyorgyi, 1978;Bagshaw and Kendrick-Jones, 1979).…”

mentioning

confidence: 99%

Hybrid myosin light chains containing a calcium‐specific site from troponin C

Silva

Kendrick‐Jones

Reinach

1992

European Journal of Biochemistry

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Recombinant DNA approaches have allowed U!j to probe the mechanisms by which the regulatory light chains (RLCs) regulate myosin function by identifying the functional importance of specific regions of the RLC molecule. For example, we have demonstrated that the presence of a high-affinity Ca2+/Mg2+-binding site in the N-terminal domain of the RLC is essential for the regulation of myosin-actin interaction [Reinach, F. C., Nagai, I(. & Kendrick-Jones, J. (1986) Nature 322, 80 -831. To explore further the role of this metal-binding site in the RLC and generate an RLC with a Ca2 +-specific site, we constructed four chicken skeletal muscle myosin regulatory light chain hybrid 'genes'. In these, the first domain containing the high-affinity CaZt/MgZt-binding site in the RLC was replaced with that containing the lower-affinity, Caz+-specific, regulatory site from troponin C (TnC). In two of these hybrids, we replaced only the Ca2+-binding EF hand, while in the other two the EF hand and the N-terminal helix of TnC were transplanted. These hybrids were expressed in Escherichia coli in high yields and the purified proteins were used in calcium-binding experiments to assay the affinity and specificity of the sites and incorporated into scallop myosin to assay their regulatory behaviour. The results obtained show that the calcium-binding site from TnC, when transplanted into the RLC backbone, had a low affinity although most of its specificity appeared to be retained. As a result, although the TnC/RLC hybrids bound to scallop myosin and were able to activate the MgATPase activity of scallop acto-myosin, they were unable to regulate it. These results are in agreement with our previous findings that occupancy of the Ca2+/MgZi site in the RLC is essential for regulation. Our results suggest that the specificity and affinity of the calcium-binding site in troponin C is dependent on both intra-and inter-domain interactions within troponin C and that these latter interactions appear to be missing when this binding site is transplanted into the light chain backbone.Motile systems based on act0 -myosin interactions are generally organized into two sets of interdigitating filaments, and the protein complex responsible for the regulation of their interaction can be located on either filament. These proteins have an inhibitory effect on actin -myosin interaction in the absence of calcium and an increase in the calcium ion concentration leads to a series of events where the inhibition is relieved (Adelstein and Eisenberg, 1980). A number of these regulatory proteins belong to the EF-hand family of calciumbinding proteins; for example troponin-C (TnC), calmodulin and the myosin essential and regulatory (RLC) light chains. They all contain four EF-hands, each consisting of a pair of almost perpendicular helices linked by a central metal-binding loop where six negative charges coordinate the metal ligand.

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Structure And Evolution Of Calcium-Modulated Protein

Cited by 957 publications

References 219 publications

Structural Characterization of a Higher Plant Calmodulin

Structural Characterization of a Higher Plant Calmodulin

The Role of Troponins in Muscle Contraction

Hybrid myosin light chains containing a calcium‐specific site from troponin C

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