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Fission Yeast Phenotype Ontology
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PMID:10611485 #1830

Closed fypoadmin closed 9 years ago

fypoadmin commented 9 years ago

absent tRNA dimethyl-guanosine modification child of abnormal tRNA methylation this modification is normally found at the 26 position, and is formed by the MF GO:0004809 tRNA (guanine-N2-)-methyltransferase activity

Original comment by: Antonialock

fypoadmin commented 9 years ago

have you requested a GO term for this? if not, I will

Original comment by: mah11

fypoadmin commented 9 years ago

better name, based on GO:0002940: tRNA N2-guanine dimethylation

Original comment by: mah11

fypoadmin commented 9 years ago

This is what I annotated to from GO:

ID GO:0004809 Name tRNA (guanine-N2-)-methyltransferase activity

ID GO:0002940 Name tRNA N2-guanine methylation Ontology Biological Process Definition The process whereby a guanine in a tRNA is methylated at the N2 position of guanine.

Original comment by: Antonialock

fypoadmin commented 9 years ago

should the term say that all G26 N2 methylation is gone (i.e. it's not monomethylated)?

Original comment by: mah11

fypoadmin commented 9 years ago

Well, they only looked for the presence of N2 methylation, and it wasn't there. The G26 bit is just "common knowledge".

Original comment by: Antonialock

fypoadmin commented 9 years ago

hang on, my question is: is there normally ONE methyl group or TWO? I'm starting to suspect it's one.

N2 refers to which nitrogen atom the methyl group is attached to.

Original comment by: mah11

fypoadmin commented 9 years ago

Original comment by: mah11

fypoadmin commented 9 years ago

added this:

abolished tRNA N2-guanine methylation FYPO:0003957

Original comment by: mah11

fypoadmin commented 9 years ago

Hmm, I think there is two based on this EC entry: http://www.chem.qmul.ac.uk/iubmb/enzyme/EC2/1/1/216.html

In the comentary to this term it says: The enzyme dissociates from its tRNA substrate between the two consecutive methylation reactions So I guess the MF only counts as one methylation event per activity for GO?

In the paper they just say that the strain lacks dimethylguanosine (determined by liquid chromatography). I tried looking at the referenced methods paper but it is a horrendous read.

Original comment by: Antonialock

fypoadmin commented 9 years ago

OK, I'll add some text to the def but otherwise leave it as is. (Updated def will make it to a release next time I edit, so I can get the rest of today's edits out there.)

Original comment by: mah11