10.1021/acs.analchem.5b01960.s001
Meghan
C. Burke
Meghan
C.
Burke
Yan Wang
Yan
Wang
Amanda E. Lee
Amanda E.
Lee
Emma Kimm Dixon
Emma Kimm
Dixon
Carlos A. Castaneda
Carlos A.
Castaneda
David Fushman
David
Fushman
Catherine Fenselau
Catherine
Fenselau
Unexpected Trypsin Cleavage at Ubiquitinated Lysines
American Chemical Society
2015
K 48 residues
trimer
Lys 48. Trypsin
R 74
ubiquitin
peptide products
tryptic conditions
Ubiquitinated LysinesUnexpected tryptic cleavage
Initial cleavage
tryptic products
Unexpected Trypsin Cleavage
2015-12-17 09:05:33
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Unexpected_Trypsin_Cleavage_at_Ubiquitinated_Lysines/2052732
Unexpected tryptic
cleavage has been characterized at modified
K48 residues in polyubiquitins. In particular, the tryptic products
of all seven of the lysine-linked dimers of ubiquitin and of three
trimerslinear Ub–<sup>48</sup>Ub–<sup>48</sup>Ub, linear Ub–<sup>63</sup>Ub–<sup>63</sup>Ub, and
the branched trimer [Ub]<sub>2</sub>–<sup>6,48</sup>Ubhave
been analyzed. In addition to the peptide products expected under
commonly used tryptic conditions, we observe that peptides are formed
with an unexpected ε-glycinylglycinyl-Lys carboxyl terminus
when the site of linkage is Lys48. Trypsin from three different commercial
sources exhibited this aberration. Initial cleavage at R74 is proposed
in a distal ubiquitin to produce a glycinylglycinyl-lysine residue
which is bound by trypsin.