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N-terminal protein sequencing.. "holes" at lysine residues.. meaning? - what kinda modifications cud've happnd? (Jun/20/2007 )

Hiii allllll!
I've got my results for the N-terminal protein sequencing.. with "holes" at lysine residues.. meaning? the signals are very very low! what does it mean. This the case where the protein was electrophoresed and transfered to a PVDF membrane before the analysis.
The sequence matches the theoritical but lysine residues show holes.. what kinda modifications cud've happnd here?? spontaneous modifications only? my protein is produced by overexpression in an e coli host and then purification. I found stuff like acetylation, methylation but i was wondering if those shud b considered in this case?? what cud possibly b the reasons here.. lemme know if u have an idea!!

Thankssssss!

-cheeztoast-

QUOTE (cheeztoast @ Jun 20 2007, 09:09 AM)
Hiii allllll!
I've got my results for the N-terminal protein sequencing.. with "holes" at lysine residues.. meaning? the signals are very very low! what does it mean. This the case where the protein was electrophoresed and transfered to a PVDF membrane before the analysis.
The sequence matches the theoritical but lysine residues show holes.. what kinda modifications cud've happnd here?? spontaneous modifications only? my protein is produced by overexpression in an e coli host and then purification. I found stuff like acetylation, methylation but i was wondering if those shud b considered in this case?? what cud possibly b the reasons here.. lemme know if u have an idea!!

Thankssssss!


lysine residues are targets of PTM; well known is hydroxy-ysine of collagen, or methylation of lysine of calmodulin

-The Bearer-

How about ubiquitination aswell as a possibility on lysine residues? Not sure about sumo-ylation also.\

Ceri

-Ceri-