Molecular Playground/Bacterial Chemotaxis Complex: Difference between revisions
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<applet load='3UR1' size='400' color='white' frame='true' align='right' caption='A single asymmetric unit ternary complex with the truncated receptor (grey), CheA (blue), and CheW (cyan) ([[3ur1]])' scene='57/571407/Single_ternary_complex/1'/> | |||
One of the [[CBI Molecules]] being studied in the [http://www.umass.edu/cbi/ University of Massachusetts Amherst Chemistry-Biology Interface Program] at UMass Amherst. | One of the [[CBI Molecules]] being studied in the [http://www.umass.edu/cbi/ University of Massachusetts Amherst Chemistry-Biology Interface Program] at UMass Amherst. | ||
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===Structure=== | ===Structure=== | ||
• The <scene name='57/571407/Cytoplasmic_receptor/1'>chemoreceptor</scene> (1QU7) – also called methyl-accepting protein, MCP – is a ~380Å long, alpha helical homo-dimer with many domains. The <scene name='57/571407/Cytoplasmic_receptor/2'>signaling domain</scene> at the cytosplasmic tip is where both CheW and CheA interact and bind. | • The <scene name='57/571407/Cytoplasmic_receptor/1'>chemoreceptor</scene> (1QU7) – also called methyl-accepting protein, MCP – is a ~380Å long, alpha helical homo-dimer with many domains. The <scene name='57/571407/Cytoplasmic_receptor/3'>methylation sites</scene> (Glu295, Glu302,Glu309, Glu491) are shown by yellow color. When <scene name='57/571407/Cheb/1'>CheB</scene> interacts with the receptor, it acts as a methylestrase by removing methyl groups from these 4 residues. On the other hand <scene name='57/571407/Cher/2'>CheR</scene> acts as methyltranferase by adding methyl groups to these residues.The <scene name='57/571407/Cytoplasmic_receptor/2'>signaling domain</scene> at the cytosplasmic tip is where both CheW and CheA interact and bind. | ||
• <scene name='57/571407/Chea_p3p4p5/1'>CheA</scene> is a large 5-subdomain (P1-P5) histidine kinase that auto-phosphorylates depending on it's interaction with the receptor and localized concentrations of the response regulator protein CheY. This scene is of P3-P5 as a homo-dimer (1B3Q). For more information, see [http://proteopedia.org/wiki/index.php/Molecular_Playground/CheA CheA Molecular Playground page] | • <scene name='57/571407/Chea_p3p4p5/1'>CheA</scene> is a large 5-subdomain (P1-P5) histidine kinase that auto-phosphorylates depending on it's interaction with the receptor and localized concentrations of the response regulator protein CheY. This scene is of P3-P5 as a homo-dimer (1B3Q). For more information, see [http://proteopedia.org/wiki/index.php/Molecular_Playground/CheA CheA Molecular Playground page] | ||
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• The small multi-functioning adaptor and scaffolding protein <scene name='57/571407/Chew/1'>CheW</scene> (2HO9) is not directly involved in the signaling event but is essential for CheA activity. | • The small multi-functioning adaptor and scaffolding protein <scene name='57/571407/Chew/1'>CheW</scene> (2HO9) is not directly involved in the signaling event but is essential for CheA activity. | ||
• When combined, these three proteins assemble into large membrane associated complex primed for relaying signals from outside the cell. <scene name='57/571407/Ternary_complex_side_view/ | • When combined, these three proteins assemble into large membrane associated complex primed for relaying signals from outside the cell. <scene name='57/571407/Ternary_complex_side_view/4'>This scene</scene> shows a top down view of a set of three ternary complexes with the receptor in gray, CheA in blue, and CheW in cyan. Recent cryo-EM data from the [http://www.pnas.org/cgi/doi/10.1073/pnas.1115719109 Crane Lab] shows evidence for extended hexagonal arrays in which the receptors exist as trimers of dimers with rings of CheA and CheW connecting them together. | ||
===Protein Interfaces=== | |||
[[Image:3UR1_4JPB_alignment.png|thumb|left|upright=1|alt=Alignment|Fig. 1 CheA and CheW alignment for 3UR1 and 4JPB]]A recent structure of the ternary complex has defined specific contacts between the protein interfaces. Although the receptor is 'unzipped' at the known hairpin loop, the specific residues at the protein-protein interfaces are still believed to be accurate because CheA and CheW align well with a previous crystal structure (Fig. 1). More information can be found [http://http://www.ncbi.nlm.nih.gov/pubmed/23668907 here] | |||
• <scene name='57/571407/Receptor_chea_interface/1'>Receptor to CheA</scene>: Residues highlighted in red are (receptor) 135, 138, 142 and (CheA) 563, 566 (4JPB) | |||
• <scene name='57/571407/Receptor_chew_interface/1'>Receptor to CheW</scene>: Residues highlighted in red are (receptor) 137, 139-143, 145, 146, 156 and (CheW) 14, 27, 30, 98, 99 (3UR1) | |||