O-GlcNAc

Richard S. Johnson (rjohnson@immunex.com)
Wed, 29 Jul 98 14:30:33 -0800

Does anyone know where one can obtain synthetic O-GlcNAc peptides? If
Gerald Hart is correct and O-GlcNAcylation is as common as
phosphorylation it seems reasonable to wonder why no one seems to come
across this modification all that frequently. In the days prior to
when mass spectrometers were in every other protein chem lab, one can
understand why this modification was overlooked. Now that mass
spectrometers are as common as vortexers, why don't people stumble
across O-GlcNAc more often. A possible explanation, according to
Gerald Hart is that O-GlcNAc is largely unstable to electrospray and
maldi (including IR MALDI). Does anyone have any experience w/
O-GlcNAc peptides or know how to obtain synthetic peptides?

Regards, Rich Johnson (rjohnson@immunex.com)

______________________________ Reply Separator _________________________________
Subject: Re: Posttranslational Modifications
Author: Ken Mitchelhill <k.mitchelhill@medicine.unimelb.edu.au> at Internet
Date: 7/29/98 1:24 PM

To: Ken Walsh

Ken,

In "the other Ken's" original post, he stated the doublet ran "about twice
the distance between the phospho and non-phosho forms of either individual
species" in isoelectric focussing.

Gerald Hart presented his "dynamic glycosylation" data at Lorne this year
and we have been looking out for it in some of the regulatory systems we
are interested in. I am curious if you, or anyone else out there, knows how
GlcNacylation would be expected to affect the isoelectric mobility of a
protein?

regards....Ken Mitchelhill

>Ken
>
>An interesting possibility for a PTM would be attachment of a single
>hexosamine (+161). Gerald Hart has found that specific glycation (with
>GlcNac I think) acts to limit phosphorylation.
>
>Ken
>
>Kenneth A. Walsh
>E.W.Davie/ZymoGenetics Chair of Biochemistry
>Box # 357350
>University of Washington
>Seattle WA 98195
>
>walsh@u.washington.edu
>Phone 206-543-1768
>FAX 206-685-9231
>
>On Mon, 27 Jul 1998, Kenneth Williams wrote:
>
>> One of our users is working with a kinase that is phosphorylated at a
>> single site. In addition, however, the non-phosphorylated (and
>> dephosphorylated) kinase migrates as a doublet on isoelectric focussing -
>> with the distance between the two (non-phosphorylated) species being about
>> twice the distance between the phospho and non-phosho forms of either
>> individual species. My question is what are the most likely
>> post-translational modifications that might give rise to the original
>> doublet (assuming one species in not modified and that neiterh is
>> phosphorylated).
>>
>> Thanks!
>>
>>
>>
>> Ken Williams, Ph.D.
>> Director, HHMI Biopolymer/Keck Laboratory
>> Professor (Adjunct) Research
>> Molecular Biophysics and Biochemistry
>>
>>
>> Visit the HHMI Biopolymer/Keck Laboratory Web Page at:
>>
>> http://info.med.yale.edu/wmkeck/
>>
>>


********************************

Ken I. Mitchelhill
The John Holt Protein Structure Laboratory
St. Vincent's Institute of Medical Research
41 Victoria Parade
Fitzroy 3065 Victoria
AUSTRALIA

Telephone: 61-3-9288 2480
Facsimile: 61-3-9416 2676

Email: k.mitchelhill@medicine.unimelb.edu.au

Laboratory: http://www.medstv.unimelb.edu.au/WWWDOCS/SVIMRdocs/JHPSL.html
ABRF: http://www.abrf.org

***********************************