1HTT:
reference: Crystal structure of histidyl-tRNA synthetase from Escherichia coli complexed with histidyl-adenylate., Arnez JG, Harris DC, Mitschler A, Rees B, Francklyn CS, Moras D, EMBO J 1995 Sep 1;14(17):4143-55. PMID: 7556055

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