The solution conformation behavior of complex oligosaccharides was studied by resonance energy transfer, as measured by the time-resolved fluorescence method, to determine the conformational heterogeneity of a triantennary glycopeptide at various temperatures. Groups that acted as a fluorescence donor (naphthyl-2-acetyl, Nap) or acceptor (dansylethylenediamine, Dan) were selectively attached to the N terminus of the peptide and a Gal residue [either 6' (shown below), 6, or 8] of the oligosaccharide, respectively. [formula: see text] Time-resolved fluorescence energy-transfer measurements revealed two populations of conformers when Dan was attached to either Gal-6' or Gal-6. One conformer contained the antenna folded back toward the core region, and a second was in an extended conformation. The two conformations differed in donor-acceptor distance by about 10 A. Systematically increasing the temperature from 0 degrees C to 40 degrees C increased the ratio of extended to folded forms 2-fold for the Gal-6 isomer and 4-fold for the Gal-6' isomer, whereas the Gal-8 isomer showed only a single distance population throughout this temperature range. From these data, delta H and delta S for the reversible conformational change were calculated to be 3.1 kcal/mol and 10.8 cal/(mol.K) for the Gal-6 isomer and 7.1 kcal/mol and 25.8 cal/(mol.K) for the Gal-6' isomer. In addition to the structural microheterogeneity commonly associated with glycoproteins, the differential flexibilities of the different branches in the oligosaccharides contribute conformational heterogeneity and should be considered in conformational analysis. The data are discussed in terms of the most probable linkages that contribute to the observed flexibility of the individual triantennary branches, and the biological significance of flexible linkages in complex carbohydrates is considered.
Pharmacology, Toxicology and Pharmaceutical Science
1
17%
Agricultural and Biological Sciences
1
17%
Unknown
1
17%
Attention Score in Context
Attention Score in Context
This research output has an Altmetric Attention Score of 3. This is our high-level measure of the quality and quantity of online attention that it has received. This Attention Score, as well as the ranking and number of research outputs shown below, was calculated when the research output was last mentioned on 09 July 2013.
All research outputs
#12,344,996
of 34,363,559 outputs
Outputs from Proceedings of the National Academy of Sciences of the United States of America
#83,657
of 118,931 outputs
Outputs of similar age
#9,645
of 25,176 outputs
Outputs of similar age from Proceedings of the National Academy of Sciences of the United States of America
#263
of 405 outputs
Altmetric has tracked 34,363,559 research outputs across all sources so far. This one is in the 38th percentile – i.e., 38% of other outputs scored the same or lower than it.
So far Altmetric has tracked 118,931 research outputs from this source. They typically receive a lot more attention than average, with a mean Attention Score of 40.1. This one is in the 13th percentile – i.e., 13% of its peers scored the same or lower than it.
Older research outputs will score higher simply because they've had more time to accumulate mentions. To account for age we can compare this Altmetric Attention Score to the 25,176 tracked outputs that were published within six weeks on either side of this one in any source. This one is in the 7th percentile – i.e., 7% of its contemporaries scored the same or lower than it.
We're also able to compare this research output to 405 others from the same source and published within six weeks on either side of this one. This one is in the 1st percentile – i.e., 1% of its contemporaries scored the same or lower than it.
