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User:Jamie Abbott/Sandbox2
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Histidyl tRNA Synthetase (HisRS) is a 94kD homodimer that belongs to the Class II of aminoacyl-tRNA synthetases (aaRS). Class II enzymes have a <scene name='User:Jamie_Abbott/Sandbox2/Catalytic_domain/1'>catalytic domain</scene> composed of anti-parallel β-sheets and α-helices (residues 1-325). | Histidyl tRNA Synthetase (HisRS) is a 94kD homodimer that belongs to the Class II of aminoacyl-tRNA synthetases (aaRS). Class II enzymes have a <scene name='User:Jamie_Abbott/Sandbox2/Catalytic_domain/1'>catalytic domain</scene> composed of anti-parallel β-sheets and α-helices (residues 1-325). | ||
| - | '''Function and Catalysis'''<StructureSection load='1KMM' size='500' side='right' caption='Structure of Histidyl-tRNA Synthetase (PDB entry [[1KMM]])' scene=''>Class II aminoacyl-tRNA synthetases aminoacylate the 3'OH of their cognate tRNAs.</StructureSection> | + | '''Function and Catalysis'''<StructureSection load='1KMM' size='500' side='right' caption='Structure of Histidyl-tRNA Synthetase (PDB entry [[1KMM]])' scene=''>Class II aminoacyl-tRNA synthetases aminoacylate the 3'OH of their cognate tRNAs. |
| + | The active site to HisRS contains a histidine binding pocket composed of highly conserved residues found in distinct sequences motifs. First, the LV/AAGGGLDYY loop (or HisA loop) forms one wall of the binding pocket. Second, the glycine-rich β-strand (sequence AGGRYDGL preceding motif 3) comprises the histidine binding pocket floor and wall. Finally, conserved side chains that make direct contact with histidine are Glu83 and Gly127 (motif II), which contact the α-amino and α-carbonyl functional groups, respectively, and Glu131 (motif II) and Tyr264, which make hydrogen bonds to the Nδ and Nε, respectively, of the imidazole ring.<ref>Cusack et.al</ref></StructureSection> | ||
<scene name='User:Jamie_Abbott/Sandbox2/Hisrsdimer/2'>Dimer</scene> | <scene name='User:Jamie_Abbott/Sandbox2/Hisrsdimer/2'>Dimer</scene> | ||
<scene name='User:Jamie_Abbott/Sandbox2/Hisrsdimer_to_monomer/2'>Monomer</scene> | <scene name='User:Jamie_Abbott/Sandbox2/Hisrsdimer_to_monomer/2'>Monomer</scene> | ||
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== Mechanism == | == Mechanism == | ||
Revision as of 19:00, 14 April 2012
Contents |
Histidyl-tRNA Synthetase
Histidyl tRNA Synthetase (HisRS) is a 94kD homodimer that belongs to the Class II of aminoacyl-tRNA synthetases (aaRS). Class II enzymes have a composed of anti-parallel β-sheets and α-helices (residues 1-325).
Function and Catalysis
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Mechanism
Structures
References
- ↑ Cusack et.al
