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I am studying carbohydrates and was wanting to know if it was possible to record correlations through the ether linkage of the glycosidic bond in sugars either from the proton or carbon of one sugar top the adjacent sugar or the protons of a Serine or threonine side chain in a glyco-peptide. Would something like a 13C-HSQC-TOCSY cross the glycosidic bond? if not are there experiments that would? |
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The ideal experiment for this is the HMBC. The delay should be optimized for ca 5 Hz coupling. The nJ(C,H) couplings across oxygens or other heteroatoms can be smaller than the corresponding ones over all carbons. You might also be able to establish connectivity with a NOESY or ROESY experiment. Thank you again Clemens, is there an easy way to measure the coupling constant? given the crowded nature of either a carbohydrate or glycosylated peptide? - Thomas Garner (Mar 22 '11 at 07:17) |
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Hi! Thomas Garner, I sent a quesry to Prof. Saikia when I read your query to which he kindly sent a reply. I am copying this correspondence for your benefit with the hope that you will find it helpful. REPLY from SAIKIADear Prof. Aravamudhan, Thank you for your mail which includes information of J- coupling and NOE. Yes, NOE is the best as HMBC not that easy for us. With best regards, Anil K. saikia Professor Department of Chemistry IIT Guwahati Guwahati 781039 INDIA My (Aravamudhan) message to Saikia:Dear Prof. Saikia, Nice meeting you in Shillong which is our meeting after a long time. I forward this message from my email box received from the nmrwiki. The question on "Correlations across Glycosidic bonds" reminded me of your 4-bond coupling (2 Hz) through an Oxygen atom in your lecture at NEHU recently which required an NOE study for confirmation. This question which you can display by clicking on the hotlink HERE: Aravamudhan |
