6.5.1.8	C100A	inactive for ligation reaction	-, 741323	
6.5.1.8	C122A	the mutant does not bind Mn2+	749256	
6.5.1.8	C78A	almost complete loss of activity	740694	
6.5.1.8	C78A	completely inactive	748103	
6.5.1.8	C78S	complete loss of activity	740694	
6.5.1.8	C98A	mutation in predicted metal-binding site, loss of activity	740053	
6.5.1.8	D75A	almost complete loss of activity	740694	
6.5.1.8	D75A	the mutation allows cyclic phosphodiester hydrolysis but cripples 3'-phosphate guanylylation	748103	
6.5.1.8	D75E	complete loss of activity	740694	
6.5.1.8	D75N	complete loss of activity	740694	
6.5.1.8	E371Q	the mutant shows reduced activity compared to the wild type enzyme	748760	
6.5.1.8	H168A	almost complete loss of activity	740694	
6.5.1.8	H168A	the mutant shows about 48% of 5'-OH-RNAp ligation activity compared to the wild type enzyme	748103	
6.5.1.8	H168N	complete loss of activity	740694	
6.5.1.8	H168Q	complete loss of activity	740694	
6.5.1.8	H185A	activity is severely impaired	740694	
6.5.1.8	H185A	the mutant shows 5'-OH-RNAp ligation activity similar to the wild type enzyme	748103	
6.5.1.8	H205A	inactive for ligation reaction	-, 741323	
6.5.1.8	H236A	inactive for ligation reaction	-, 741323	
6.5.1.8	H280A	active, protein is able to complement a Saccharomyces cerevisiae Trl1 mutant	740694	
6.5.1.8	H281A	the mutant is impaired in overall 5'-OH-RNAp and 5'-OH-RNA-2',3'-cyclic phosphate ligation but is able to seal a preguanylylated substrate	748103	
6.5.1.8	H337A	almost complete loss of activity	740694	
6.5.1.8	H337A	His337 is the site covalent guanylylation of RtcB, mutant is inactive	741074	
6.5.1.8	H337A	residue His337 is the site of covalent guanylylation, the mutation abolishes 3'-phosphate/5'-OH RNA ligation	741327	
6.5.1.8	H337A	the mutant shows about 1% of 5'-OH-RNAp ligation activity compared to the wild type enzyme	748103	
6.5.1.8	H337N	complete loss of activity	740694	
6.5.1.8	H337N	residue His337 is the site of covalent guanylylation, the mutation abolishes 3'-phosphate/5'-OH RNA ligation	741327	
6.5.1.8	H337Q	complete loss of activity	740694	
6.5.1.8	H337Q	residue His337 is the site of covalent guanylylation, the mutation abolishes 3'-phosphate/5'-OH RNA ligation	741327	
6.5.1.8	H601Q	the mutant shows reduced activity compared to the wild type enzyme	748760	
6.5.1.8	K298A	activity is severely impaired	740694	
6.5.1.8	K299A	the mutant shows about 50% of 5'-OH-RNAp ligation activity compared to the wild type enzyme	748103	
6.5.1.8	K52N	the mutant shows reduced activity compared to the wild type enzyme	748760	
6.5.1.8	N167A	activity is severely impaired	740694	
6.5.1.8	N167A	the mutant shows about 65% of 5'-OH-RNAp ligation activity compared to the wild type enzyme	748103	
6.5.1.8	R189A	activity is severely impaired	740694	
6.5.1.8	R189A	almost complete loss of activity	740694	
6.5.1.8	R189A	the mutation slows the step of RNAppG/5'-OH RNA sealing by a factor of 200 compared to that with wild type enzyme while decreasing the rate of RNAppG formation by 3fold	748103	
6.5.1.8	R341A	almost complete loss of activity	740694	
6.5.1.8	R341A	the mutant shows about 10% of 5'-OH-RNAp ligation activity compared to the wild type enzyme	748103	
6.5.1.8	R345A	the mutant shows 5'-OH-RNAp ligation activity similar to the wild type enzyme	748103	
6.5.1.8	R557K	the mutant shows reduced activity compared to the wild type enzyme	748760