Sandbox Reserved 657: Difference between revisions
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Spo0F is a 14KDa (2), 36 by 34 by 31 angstrom single domain globular protein (6) containing 124 residue (4). The protein consists of 45% helical secondary structures and 21% beta sheets structure (4). There are 5 helices and 5 beta sheets present within the polypeptide collectively made using 57 residues and 27 residues respectively (4). The structure is further classified as an alpha and beta protein in the CheY superfamily, with folds classified as Flavodoxin-like folding (4). The tertiary structure is a “double wound (beta/alpha) motif formed [by the] five parallel beta strands flanked by alpha helicies” (2). The helices and strands are parallel in comparison to themselves however in contrast to each other, i.e, beta to helix, they are opposite (6).The hydrophobic core of spo0F is made up of beta strand one, three, four, and five; each of these helices being amphiphathic (6, 1). The majority of the protein surface is covered with hydrophilic residues, however there are two hydrophobic regions present on the face of the peptide. These hydrophobic surface regions are found by the N-terminus of helix five; it is speculated that this interaction is important in the response regulation of spo0F and protein protein interaction (6, 1, 7). AS well, the side chains are highly ordered is the classical staggering conformation. From the most energetically enssamble of potential structures the side chains are withing 30 degrees of the staggered ordering (1). | Spo0F is a 14KDa (2), 36 by 34 by 31 angstrom single domain globular protein (6) containing 124 residue (4). The protein consists of 45% helical secondary structures and 21% beta sheets structure (4). There are 5 helices and 5 beta sheets present within the polypeptide collectively made using 57 residues and 27 residues respectively (4). The structure is further classified as an alpha and beta protein in the CheY superfamily, with folds classified as Flavodoxin-like folding (4). The tertiary structure is a “double wound (beta/alpha) motif formed [by the] five parallel beta strands flanked by alpha helicies” (2). The helices and strands are parallel in comparison to themselves however in contrast to each other, i.e, beta to helix, they are opposite (6).The hydrophobic core of spo0F is made up of beta strand one, three, four, and five; each of these helices being amphiphathic (6, 1). The majority of the protein surface is covered with hydrophilic residues, however there are two hydrophobic regions present on the face of the peptide. These hydrophobic surface regions are found by the N-terminus of helix five; it is speculated that this interaction is important in the response regulation of spo0F and protein protein interaction (6, 1, 7). AS well, the side chains are highly ordered is the classical staggering conformation. From the most energetically enssamble of potential structures the side chains are withing 30 degrees of the staggered ordering (1). | ||
The active site of spo0F is present within buried and exposed portions of the secondary structure found at the C-terminus of the central beta sheet (6). The active site is made up of four residues, three alanines (D10,D11,D54) and a lysine (K104), with all the active residues on a single face (1,2, 6). D54 is shown to be the specific site of phosphorylation in spo0F (6) The active site itself accommidates a magnesium ion, to be used as a cofactor in the phosphate transfer, and Cl- for stability (6). The calcium bound at the aspartate pocket stabilizes a octahedral structure of the binding pocket by interacting with the carboxylate residues of D11 and D54, and carbonyl group of K56. This calcium ion is also shown to stimulate the enzymatic process. The other binding positions are bound to water molecules for increased stability(6). However, the phosphorylation reaction is dependent upon Thr82 and its hydroxyl group, this residue may sometimes may be functionally mutated to a Ser residue. The Thr82 is essential in the phosphotransfer reaction but does not assist in recognition and binding of other proteins in the phospohrelay chain (2). | The active site of spo0F is present within buried and exposed portions of the secondary structure found at the C-terminus of the central beta sheet (6). The active site is made up of four residues, three alanines (D10,D11,D54) and a lysine (K104), with all the active residues on a single face (1,2, 6) . D54 is shown to be the specific site of phosphorylation in spo0F (6) The active site itself accommidates a magnesium ion, to be used as a cofactor in the phosphate transfer, and Cl- for stability (6). The calcium bound at the aspartate pocket stabilizes a octahedral structure of the binding pocket by interacting with the carboxylate residues of D11 and D54, and carbonyl group of K56. This calcium ion is also shown to stimulate the enzymatic process. The other binding positions are bound to water molecules for increased stability(6). However, the phosphorylation reaction is dependent upon Thr82 and its hydroxyl group, this residue may sometimes may be functionally mutated to a Ser residue. The Thr82 is essential in the phosphotransfer reaction but does not assist in recognition and binding of other proteins in the phospohrelay chain (2). | ||
<scene name='Sandbox_Reserved_657/Activesitescene/1'>Spo0F Active Site</scene> | |||
The active site itself is regulated by phospohrylation. If spo0F is not phosphorylated the active site is inaccessible ; when phospohorylated a conformational change occurs opening the active site (6). This phosphorylation is regulated by a histadine kinase (3). Otherwise the protein itself lacks an effector domain (6). | The active site itself is regulated by phospohrylation. If spo0F is not phosphorylated the active site is inaccessible ; when phospohorylated a conformational change occurs opening the active site (6). This phosphorylation is regulated by a histadine kinase (3). Otherwise the protein itself lacks an effector domain (6). | ||