Thanks to everyone who gave suggestions on this issue. Neil Gilkes
brought my attention to a pertinent review article, Sandercock et al.,
"Non-S-layer glycoproteins in eubacteria," FEMS Microbiology Letters 118:
1-8, 1994. The upshot appears to be that many species of bacteria DO
glycosylate proteins, via sugars and linkages that are different from those
described (so far) in eukaryotes. (A bacterial-type linkage was recently
reported in eukaryotic laminin, so there may be some overlap after all.)
On the other hand, no one seems to have described glycosylation
specifically in E. Coli, the bacterial species most used for making
recombinant proteins. It remains unclear whether E. Coli is really
different from the bacteria that do glycosylate -- or the basis and
significance of this difference. Is the entire enzymatic machinery missing,
or just one critical core step? What is the ecological benefit for a
species to have, or lack, glycosylation of its proteins?
Neil Smalheiser
sma2 at midway.uchicago.edu
