Sandbox Reserved 657: Difference between revisions
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The signal transduction pathway begins by the celularl ATP-dependant autophosphorylation ofhistadine kinase A and B in response to specific envirionmental conditions <ref>2</ref>; this mechenism is still uknown. Spo0F is then phosphorylated by KinA at spo0F’s active site. This phosphorylation creates a confromtaions change to spo0F <ref>1</ref><ref>2</ref><ref>6</ref> which then activetes its kinase properties. Once activated, spo0F is able to phospohrylate spo0A through a phosphoramidate intermediate spo0B <ref>1</ref><ref>2</ref>. Spo0B acts as a phosphotransferase between spo0F and A, which reacts reverable between the two kinases <ref>2</ref>. Once phosphorylated, spo0A is in its active transcriptional reulator form and initiates the transcriptions of spoulation proteins and spore formation may begin. | The signal transduction pathway begins by the celularl ATP-dependant autophosphorylation ofhistadine kinase A and B in response to specific envirionmental conditions <ref>2</ref>; this mechenism is still uknown. Spo0F is then phosphorylated by KinA at spo0F’s active site. This phosphorylation creates a confromtaions change to spo0F <ref>1</ref><ref>2</ref><ref>6</ref> which then activetes its kinase properties. Once activated, spo0F is able to phospohrylate spo0A through a phosphoramidate intermediate spo0B <ref>1</ref><ref>2</ref>. Spo0B acts as a phosphotransferase between spo0F and A, which reacts reverable between the two kinases <ref>2</ref>. Once phosphorylated, spo0A is in its active transcriptional reulator form and initiates the transcriptions of spoulation proteins and spore formation may begin. | ||
[[Image:sporulationprocess.jpg]] | [[Image:sporulationprocess.jpg]] | ||
Figure 1: The pathways for vegitative or spore development in bacterial cells. The figure prensents the phosphorelay involving Histidine Kinase (HK) and the phosphorylation relay between Spo0f/b/a, and the method for cell development to stop sporulation <ref>3</ref>. | |||
The phosphorylation and hydrolysis of Spo0F is dependant upon a magnesium ion cofactor that binds to the active site, and a histidine autokinase <ref>1</ref><ref>2</ref><ref>7</ref>. It is hypothesized that the Mg ion is used to stablalize the transition state for the phosphoryl-transfer and hydrolysis reactions <ref>1</ref>. A unique characteristic of spo0F in comparison to other response regulatory proteins is the low binding affinity for magnesium, thus leading to a decreased stablility of the transition state. The decreased stablility of the transition state leads to spo0F having longer phosphrylated life time than other similar enzymes leading to the selectivety of the enzyme. It is shown the affinity difference between response regulator enzymes, such as spo0F, is due to the non-conserved sequence within the protein <ref>1</ref>. | The phosphorylation and hydrolysis of Spo0F is dependant upon a magnesium ion cofactor that binds to the active site, and a histidine autokinase <ref>1</ref><ref>2</ref><ref>7</ref>. It is hypothesized that the Mg ion is used to stablalize the transition state for the phosphoryl-transfer and hydrolysis reactions <ref>1</ref>. A unique characteristic of spo0F in comparison to other response regulatory proteins is the low binding affinity for magnesium, thus leading to a decreased stablility of the transition state. The decreased stablility of the transition state leads to spo0F having longer phosphrylated life time than other similar enzymes leading to the selectivety of the enzyme. It is shown the affinity difference between response regulator enzymes, such as spo0F, is due to the non-conserved sequence within the protein <ref>1</ref>. | ||
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<ref>6</ref> Madhusudan, James Z., John M. Whiteley, James A. Hoch, Nguyen H. Xuong, and Kottayil I. Varughese. "Crystal Structure of a Phosphatase-resistant Mutant of Sporulation Response Regulator Spo0F from Bacillus Subtilis." Current Biology 4(1996): 679-690. Web. 24 Nov. 2012. <http://www.sciencedirect.com.prox.lib.ncsu.edu/science/article/pii/S0969212696000743>. | <ref>6</ref> Madhusudan, James Z., John M. Whiteley, James A. Hoch, Nguyen H. Xuong, and Kottayil I. Varughese. "Crystal Structure of a Phosphatase-resistant Mutant of Sporulation Response Regulator Spo0F from Bacillus Subtilis." Current Biology 4(1996): 679-690. Web. 24 Nov. 2012. <http://www.sciencedirect.com.prox.lib.ncsu.edu/science/article/pii/S0969212696000743>. | ||
<ref>7</ref> Perego, M., Hanstein, C., Welsh, K. M., Diavakhishvili, T., Glaser, P. & Hoch, J. A. (1994). Multiple proteinaspartate phosphatases provide a mechanism for the integration of diverse signals in the control of development in B. subtilis. Cell, 79, | <ref>7</ref> Perego, M., Hanstein, C., Welsh, K. M., Diavakhishvili, T., Glaser, P. & Hoch, J. A. (1994). Multiple proteinaspartate phosphatases provide a mechanism for the integration of diverse signals in the control of development in B. subtilis. Cell, 79, 1047-1055. | ||