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Amino acid sequences calmodulin-binding domains

More recently, workers in Japan published the solution structure of yeast (Saccharomyces cerevisiae) apo-calmodulin (PDB ILKJ). Yeast calmodulin is 60% identical in its amino acid sequence with vertebrate CaMs. The ILKJ N-terminal domain with its two helix-loop-helix calcium-binding domains looks quite similar to those of IDMO and ICFD (see Figure 6.23). [Pg.306]

Fig. 8. Amino acid sequences of the model calmodulin-binding peptide, CBPS, and of the proposed calmodulin-binding domains of four calmodulin-dependent kinases. The + symbols on the bottom row indicate positions where a positively charged residue occurs in at least half of the aligned sequences, the Hb symbol refers to positions generally occupied by hydrophobic residues. Fig. 8. Amino acid sequences of the model calmodulin-binding peptide, CBPS, and of the proposed calmodulin-binding domains of four calmodulin-dependent kinases. The + symbols on the bottom row indicate positions where a positively charged residue occurs in at least half of the aligned sequences, the Hb symbol refers to positions generally occupied by hydrophobic residues.
Fig. 9. Helical net diagram (Crick, 1953) of a model calmodulin-binding peptide and the putative calmodulin-binding domains of two forms of myosin light-chain kinase (MLCK). The sequences are drawn together on a single helical net and are taken from (clockwise from left) the model peptide described by DeGrado et al. (1985), skeletal muscle MLCK peptide 342-359 (Edelman et al., 1985), and the N-terminal 18 residues of a peptide derived from smooth muscle MLCK (Lucas et al., 1986). The amino acids in the sequences are given in single letter codes. Positions that are hydrophobic in all three sequences are indicated by shading. Fig. 9. Helical net diagram (Crick, 1953) of a model calmodulin-binding peptide and the putative calmodulin-binding domains of two forms of myosin light-chain kinase (MLCK). The sequences are drawn together on a single helical net and are taken from (clockwise from left) the model peptide described by DeGrado et al. (1985), skeletal muscle MLCK peptide 342-359 (Edelman et al., 1985), and the N-terminal 18 residues of a peptide derived from smooth muscle MLCK (Lucas et al., 1986). The amino acids in the sequences are given in single letter codes. Positions that are hydrophobic in all three sequences are indicated by shading.
The information derived from the analysis of this example was used as distance restraints for calculation of the 3D structure of the complex of calmodulin, a calcium binding protein, and a peptide ligand. The amino acid sequence of the peptide ligand, C20W, corresponds to the N-terminal part of the calmodulin-binding domain of the plasma membrane calcium pump (125). [Pg.1285]

Figure 9. Map of the primary amino acid sequence of nNOS, eNOS, and iNOS. A calcium-calmodulin binding region separates the oxygenase and reductase domains. The reductase domain contains binding sites for two flavin cofactors (FAD and FMN) as well as a binding site for the electron donor, NADPH. The oxygenase domain contains binding sites for the heme, the substrate (L-arginine), and tetrahyrobiopterin (H4B). (Adapted from Ref. [90].)... Figure 9. Map of the primary amino acid sequence of nNOS, eNOS, and iNOS. A calcium-calmodulin binding region separates the oxygenase and reductase domains. The reductase domain contains binding sites for two flavin cofactors (FAD and FMN) as well as a binding site for the electron donor, NADPH. The oxygenase domain contains binding sites for the heme, the substrate (L-arginine), and tetrahyrobiopterin (H4B). (Adapted from Ref. [90].)...
The NOSs are best characterized as cytochrome P-450-like hemeprot-eins (Bredt et al., 1991 Stuehr and Ikeda, 1992 White and Marietta, 1992). They can be broadly divided into a reductase domain at the COOH terminus and an oxidative domain at the NH2 terminus (Fig. 1). The primary amino acid sequences of NOS isoforms share common consensus sequence binding sites for calmodulin, NADPH, flavin-adenine dinucleotide (FAD), and flavin mononucleotide (FMN) (Bredt et al., 1991 Marsden et al., 1992 Sessa et al., 1992 Xie et al., 1992 Lyons et al., 1992 Lowenstein et al., 1992). Each enzyme functions as a dimeric protein in catalyzing the NADPH-dependent five-electron oxidation of L-arginine to generate NO. L-Citrulline is a by-product (Back et al., 1993 Abu and Stuehr, 1993). Electrons are supplied by NADPH, transferred along the flavins and calmodulin, and presented to the catalytic heme center (Stuehr and Ikeda, 1992 White and Marietta, 1992). The NOS apoenzyme requires tetrahydrobiopterin, prosthetic heme (ferroprotoporphyrin IX), calmodulin, FMN, and FAD as cofactors for monomer assembly and/or catalytic activity (Abu and Stuehr, 1993 Mayer and Werner, 1994 Kwon etal., 1989 Stuehr and Ikeda, 1992 Stuehr and Griffith, 1992 White and Marietta, 1992 McMillan etal., 1992 Klatt... [Pg.72]

Cloning of the isozyme has revealed that NOS subunits are divided into a reductase and an oxygenase domain, and the sequence that binds calmodulin is a link between these domains. The likely function of the flavins is to store electrons derived from NADPH and transfer them to the catalytic center located on the oxygenase domain. This domain is represented by a highly conserved 320-amino acid sequence of NOS that is likely to contain binding sites for heme, BH4, and L-arginine. [Pg.116]

Calmodulin has a MW % 16,700 and its primary sequence is homologous with that of parvalbumins and skeletal muscle TnC. Its amino acid sequence can be divided into four internally homologous domains, each with a potential calcium binding site(16). Most studies have indeed indicated that calmodulin can bind 4 mol of Ca " per mol of protein but there is some disagreement as regards the relative number of high and low affinity sites. [Pg.201]

Fig. 3. The EF domain. The EF primordial gene is regarded as consisting of coding sequences for one domain an a-helix of about eight amino acids (E), a calcium binding loop of about twelve amino acids (EF loop) and another region of a-helix (F). The EF domains are joined by linker sequences. Calcium coordination is accomplished by oxygen atoms of six amino acids of EF loop. Shown in this figure is the structure of the EF domain I of calmodulin. Fig. 3. The EF domain. The EF primordial gene is regarded as consisting of coding sequences for one domain an a-helix of about eight amino acids (E), a calcium binding loop of about twelve amino acids (EF loop) and another region of a-helix (F). The EF domains are joined by linker sequences. Calcium coordination is accomplished by oxygen atoms of six amino acids of EF loop. Shown in this figure is the structure of the EF domain I of calmodulin.
When proteins fold into their tertiary structures, there are often subdivisions within the protein, designated as domains, which are characterised by similar features or motifs. A protein domain is a part of the protein sequence and structure that can evolve, function and exist independently of the rest of the protein chain. Many proteins consist of several structural domains. One domain may appear in a variety of evolutionarily related proteins. Domains vary in length from about 25 up to 500 amino acids. The shortest domains, such as zinc fingers , are stabilised by metal ions or disulfide bridges. Domains often form functional units, such as the calcium-binding EF hand domain of calmodulin. As they are self-stable, domains can be swapped by genetic engineering between one protein and another, to make chimera proteins. [Pg.143]


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Acidic domains

Amino acid sequence

Amino acid sequencers

Amino acid sequences sequencing

Amino acid sequencing

Binding amino acids

Calmodulin

Calmodulin binding

Calmodulins

Domain sequence

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