User:Emma Ste.Marie/Sandbox 1: Difference between revisions
From Proteopedia
Jump to navigationJump to search
No edit summary |
No edit summary |
||
| Line 42: | Line 42: | ||
'''Interaction of mTrxR with Trx:''' | '''Interaction of mTrxR with Trx:''' | ||
The first crystal structure of Type 1 mTrxR in complex with its Trx substrate was solved by Karin Fritz-Wolf, et al. in 2011 and gave much information into structural details of the enzyme. The N-terminally located redox active disulfide (Cys59-Cys64) is buried in the protein, whereas the second, C-terminally located redox active selenosulfide (Cys497-Sec498) is positioned on a flexible, highly accessible C-terminal tail of the other subunit[5]. Complex formation of mTrxR1 with Trx involves the generation of an intermolecular disulphide bond between the catalytic residues Cys32 of Trx and Sec498 of mTrxR1, which is stabilized by several other interactions. Some of the other interactions include: hydrophobic packing (mainly Trp resudies buried with their indole rings at the interface region), hydrogen bonds between amino acid side chain residues, and other interactions involving several oppositely charged residues (electrostatic interactions). All residues involved in forming the intermediate are highly conserved in mammals[5]. It is important to note in this crystal structure that penultimate Sec residues (one on each monomer) were mutated to Cys residues (''E. coli'', the expression vector used, does not have the machinery to incorporate Sec into proteins). Additionally, the resolving Cys residue was mutated to alanine to keep Trx bound. | The first crystal structure of Type 1 mTrxR in complex with its Trx substrate was solved by Karin Fritz-Wolf, et al. in 2011 and gave much information into structural details of the enzyme. The N-terminally located redox active disulfide (<scene name='78/785330/N-_terminal_disulfide/1'>Cys59-Cys64</scene>) is buried in the protein, whereas the second, C-terminally located redox active selenosulfide (Cys497-Sec498) is positioned on a flexible, highly accessible C-terminal tail of the other subunit[5]. Complex formation of mTrxR1 with Trx involves the generation of an intermolecular disulphide bond between the catalytic residues Cys32 of Trx and Sec498 of mTrxR1, which is stabilized by several other interactions. Some of the other interactions include: hydrophobic packing (mainly Trp resudies buried with their indole rings at the interface region), hydrogen bonds between amino acid side chain residues, and other interactions involving several oppositely charged residues (electrostatic interactions). All residues involved in forming the intermediate are highly conserved in mammals[5]. It is important to note in this crystal structure that penultimate Sec residues (one on each monomer) were mutated to Cys residues (''E. coli'', the expression vector used, does not have the machinery to incorporate Sec into proteins). Additionally, the resolving Cys residue was mutated to alanine to keep Trx bound. | ||
[[Image:Ctermredoxsmall.png|800px|right|thumb|PDB: 3QFA with features highlighted. C-terminal redox centre of mTrxR: green ribbons are one monomer of mTrxR1, and blue ribbons are the other monomer. In this crystal structure, Trx (yellow ribbons) is bound to mTrxR1, and this disulfide linkage is highlighted by yellow and green spheres. It is important to note that Sec498 was mutated to Cys498, and this Cys498 residue is shown forming a disulfide with Trx. Shown in green stick is another mutation: in this crystal structure, the resolving Cys residue was mutated to Alanine to ensure Trx stays bound to mTrxR1.]] | [[Image:Ctermredoxsmall.png|800px|right|thumb|PDB: 3QFA with features highlighted. C-terminal redox centre of mTrxR: green ribbons are one monomer of mTrxR1, and blue ribbons are the other monomer. In this crystal structure, Trx (yellow ribbons) is bound to mTrxR1, and this disulfide linkage is highlighted by yellow and green spheres. It is important to note that Sec498 was mutated to Cys498, and this Cys498 residue is shown forming a disulfide with Trx. Shown in green stick is another mutation: in this crystal structure, the resolving Cys residue was mutated to Alanine to ensure Trx stays bound to mTrxR1.]] | ||
