产品内容
本酶催化的反应为(1) ATP + (Deoxyribonucleotide)n-3'-Hydroxyl + 5'-Phospho-(Deoxyribonucleotide)m = (Deoxyribonucleotide)n+m + AMP + Diphosphate (Overall Reaction);;(1a) ATP + [DNA Ligase]-L-Lysine = 5'-Adenosyl [DNA Ligase]-Nepsilon-Phosphono-L-Lysine + Diphosphate;;(1b) 5'-Adenosyl [DNA Ligase]-Nepsilon-Phosphono-L-Lysine + 5'-Phospho-(Deoxyribonucleotide)m = 5'-(5'-Diphosphoadenosine)-(Deoxyribonucleotide)m + [DNA Ligase]-L-Lysine;;(1c) (Deoxyribonucleotide)n-3'-Hydroxyl + 5'-(5'-Diphosphoadenosine)-(Deoxyribonucleotide)m = (Deoxyribonucleotide)n+m + AMP;;(2) NAD + (Deoxyribonucleotide)n-3'-Hydroxyl + 5'-Phospho-(Deoxyribonucleotide)m = (Deoxyribonucleotide)n+m + AMP + beta-Nicotinamide D-Nucleotide (Overall Reaction);;(2a) NAD + [DNA Ligase]-L-Lysine = 5'-Adenosyl [DNA Ligase]-Nepsilon-Phosphono-L-Lysine + beta-Nicotinamide D-Nucleotide;;(2b) 5'-Adenosyl [DNA Ligase]-Nepsilon-Phosphono-L-Lysine + 5'-Phospho-(Deoxyribonucleotide)m = 5'-(5'-Diphosphoadenosine)-(Deoxyribonucleotide)m + [DNA Ligase]-L-Lysine;;(2c) (Deoxyribonucleotide)n-3'-Hydroxyl + 5'-(5'-Diphosphoadenosine)-(Deoxyribonucleotide)m = (Deoxyribonucleotide)n+m + AMP，系统名称为Poly(deoxyribonucleotide)-3'-Hydroxyl:5'-Phospho-Poly(deoxyribonucleotide) Ligase (ATP Or NAD+)，来自古菌烟色热球菌 Thermococcus fumicolans 和 Thermococcus onnurineus 的这些酶对ATP或NAD+显示高活性，对TTP、GTP和CTP的活性显著较低。该酶催化连接具有3'-羟基和5'-磷酸末端的DNA链，形成磷酸二酯键并封闭双链DNA中某些类型的单链断裂。催化按三步机制进行：首先ATP或NAD+激活酶，在腺苷酸与一个赖氨酸残基之间形成磷酰胺键；随后腺苷酸基团转移到底物的5'-磷酸末端，形成加帽结构5'-(5'-二磷酸腺苷)-[DNA]；最后该酶催化3'-OH末端对加帽末端的亲核进攻，形成磷酸二酯键并释放腺苷酸。与 EC 6.5.1.1（DNA连接酶（ATP））、EC 6.5.1.2（DNA连接酶（NAD+））和 EC 6.5.1.7（DNA连接酶（ATP、ADP或GTP））不同。
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