Enzyme I of the Phosphoenolpyruvate:Sugar Phosphotransferase System: Difference between revisions
No edit summary |
Eric Martz (talk | contribs) |
||
| (7 intermediate revisions by 4 users not shown) | |||
| Line 1: | Line 1: | ||
==Enzyme I | ==Enzyme I of the PTS - a Molecular machine== | ||
<big> | |||
*[https://www.youtube.com/watch?v=qE-g6A4bH5E '''VIDEO of the PTS Enzyme in Action'''] | |||
*[https://www.youtube.com/watch?v=hxuBouGfs_4 '''VIDEO of the Pyruvate Phosphate Dikinase Enzyme in Action'''] | |||
** Video source: [https://www.ibbr.umd.edu/groups/herzberg Osnat Herzberg Group] | |||
</big> | |||
[[Image:Pts.jpg|left|thumb|'''The PTS'''|400px]]<br> | [[Image:Pts.jpg|left|thumb|'''The PTS'''|400px]]<br> | ||
Bacteria evolved a unique mechanism to import many carbohydrates, the '''phosphoenolpyruvate:sugar phosphotransferase system''' (PTS). The PTS synchronizes the transport and phosphorylation of the sugar (group translocation), engaging several proteins in a five steps phosphorylation cascade. With some variations, the PTS comprises three proteins: In the cytoplasm, PEP phosphorylates '''Enzyme I''' (EI), which then transfers the phosphoryl group to the histidine phosphocarrier protein, HPr. From HPr, the phosphoryl group is transferred to various sugar-specific membrane associated transporters (EnzII), each comprising two cytoplasmic domains, EIIA and EIIB, and an integral membrane domain EIIC. Within EII, EIIA accepts the phosphoryl group from HPr and donates it to EIIB, whereupon EIIC mediates sugar translocation with EIIB providing the phosphoryl group. In addition to controlling sugar translocation, the phosphorylation state of PTS proteins is also associated with regulation of metabolic pathways and signaling in bacterial cells.<br> | Bacteria evolved a unique mechanism to import many carbohydrates, the '''phosphoenolpyruvate:sugar phosphotransferase system''' (PTS). The PTS synchronizes the transport and phosphorylation of the sugar (group translocation), engaging several proteins in a five steps phosphorylation cascade. With some variations, the PTS comprises three proteins: In the cytoplasm, PEP phosphorylates '''Enzyme I''' (EI), which then transfers the phosphoryl group to the histidine phosphocarrier protein, HPr. From HPr, the phosphoryl group is transferred to various sugar-specific membrane associated transporters (EnzII), each comprising two cytoplasmic domains, EIIA and EIIB, and an integral membrane domain EIIC. Within EII, EIIA accepts the phosphoryl group from HPr and donates it to EIIB, whereupon EIIC mediates sugar translocation with EIIB providing the phosphoryl group. In addition to controlling sugar translocation, the phosphorylation state of PTS proteins is also associated with regulation of metabolic pathways and signaling in bacterial cells.<br> | ||
| Line 11: | Line 12: | ||
'''''The movie''' depicts the phosphotransfer from PEP to EI and from EI to HPr and the accompanying protein conformational transitions. This is a model based on crystal structure of the intact E. coli EI and the NMR model of the fragment containing the HPr-binding domain and the His-domain in complex with HPr. The HPr-binding domain is colored blue. The PEP-binding domain is colored cyan, the His-domain is colored yellow, and the linker segments that connect the His-domain to the partner domains are colored red. Hpr is colored green. Ligands and the catalytic histidine are depicted in stick models with the atomic color scheme: Carbon – gray, Nitrogen – blue, Oxygen – red, Phosphorous – green, Magnesium – magenta. The movie was created by Kap Lim and osnat Herzberg'' | '''''The movie''' depicts the phosphotransfer from PEP to EI and from EI to HPr and the accompanying protein conformational transitions. This is a model based on crystal structure of the intact E. coli EI and the NMR model of the fragment containing the HPr-binding domain and the His-domain in complex with HPr. The HPr-binding domain is colored blue. The PEP-binding domain is colored cyan, the His-domain is colored yellow, and the linker segments that connect the His-domain to the partner domains are colored red. Hpr is colored green. Ligands and the catalytic histidine are depicted in stick models with the atomic color scheme: Carbon – gray, Nitrogen – blue, Oxygen – red, Phosphorous – green, Magnesium – magenta. The movie was created by Kap Lim and osnat Herzberg'' | ||
==Additional Resources== | |||
[[User:Karl_Oberholser/Phosphoenolpyruvate:Sugar_Phosphotransferase|Larger movie frame]] for classroom projection <br> | |||
For additional information, see: [[Membrane Channels & Pumps]] <br /> | |||
For additional information, see: [[Photosynthesis]] | |||
<br /> | |||
== Key References == | == Key References == | ||
| Line 18: | Line 25: | ||
#Garrett, D. S., Seok, Y. J., Peterkofsky, A., Gronenborn, A. M., & Clore, G. M. (1999). Solution structure of the 40,000 Mr phosphoryl transfer complex between the N-terminal domain of enzyme I and HPr. Nat. Struct. Biol. 6, 166-173. | #Garrett, D. S., Seok, Y. J., Peterkofsky, A., Gronenborn, A. M., & Clore, G. M. (1999). Solution structure of the 40,000 Mr phosphoryl transfer complex between the N-terminal domain of enzyme I and HPr. Nat. Struct. Biol. 6, 166-173. | ||
== | == 3D Structures of EI == | ||
[[Phosphotransferase]] | |||