:23S rRNA (guanine745-N1)-methyltransferase

{{Short description|Class of enzymes}}

{{Infobox enzyme

| Name = 23S rRNA (guanine⁷⁴⁵-N¹)-methyltransferase

| EC_number = 2.1.1.187

| CAS_number =

| GO_code =

| image =

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23S rRNA (guanine⁷⁴⁵-N¹)-methyltransferase ({{EC number|2.1.1.187}}, Rlma(I), Rlma1, 23S rRNA m1G745 methyltransferase, YebH, RlmAI methyltransferase, ribosomal RNA(m1G)-methylase, rRNA(m1G)methylase, RrmA, 23S rRNA:m1G745 methyltransferase) is an enzyme with systematic name S-adenosyl-L-methionine:23S rRNA (guanine⁷⁴⁵-N¹)-methyltransferase.{{cite journal | vauthors = Liu M, Novotny GW, Douthwaite S | title = Methylation of 23S rRNA nucleotide G745 is a secondary function of the RlmAI methyltransferase | journal = RNA | volume = 10 | issue = 11 | pages = 1713–20 | date = November 2004 | pmid = 15388872 | pmc = 1370659 | doi = 10.1261/rna.7820104 }}{{cite journal | vauthors = Gustafsson C, Persson BC | title = Identification of the rrmA gene encoding the 23S rRNA m1G745 methyltransferase in Escherichia coli and characterization of an m1G745-deficient mutant | journal = Journal of Bacteriology | volume = 180 | issue = 2 | pages = 359–65 | date = January 1998 | doi = 10.1128/JB.180.2.359-365.1998 | pmid = 9440525 | pmc = 106891 }}{{cite journal | vauthors = Das K, Acton T, Chiang Y, Shih L, Arnold E, Montelione GT | title = Crystal structure of RlmAI: implications for understanding the 23S rRNA G745/G748-methylation at the macrolide antibiotic-binding site | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 101 | issue = 12 | pages = 4041–6 | date = March 2004 | pmid = 14999102 | pmc = 384692 | doi = 10.1073/pnas.0400189101 | bibcode = 2004PNAS..101.4041D | doi-access = free }}{{cite journal | vauthors = Hansen LH, Kirpekar F, Douthwaite S | title = Recognition of nucleotide G745 in 23 S ribosomal RNA by the rrmA methyltransferase | journal = Journal of Molecular Biology | volume = 310 | issue = 5 | pages = 1001–10 | date = July 2001 | pmid = 11501991 | doi = 10.1006/jmbi.2001.4836 }}{{cite journal | vauthors = Liu M, Douthwaite S | title = Methylation at nucleotide G745 or G748 in 23S rRNA distinguishes Gram-negative from Gram-positive bacteria | journal = Molecular Microbiology | volume = 44 | issue = 1 | pages = 195–204 | date = April 2002 | pmid = 11967079 | doi = 10.1046/j.1365-2958.2002.02866.x | doi-access = free }} This enzyme catalyses the following chemical reaction

: S-adenosyl-L-methionine + guanine⁷⁴⁵ in 23S rRNA $\backslash rightleftharpoons$ S-adenosyl-L-homocysteine + N¹-methylguanine⁷⁴⁵ in 23S rRNA

The enzyme specifically methylates guanine⁷⁴⁵ at N¹ in 23S rRNA.