This webportal is currently unavailable
UPLABEL (Unique Pair Labeling) is an algorithm for finding optimal labeling patterns for the backbone assignment of proteins that cannot be assigned by conventional methods. Following the approach of Kainosho and Tsuji (Biochemistry 21:6273–6279 (1982)), certain types of amino acids are labeled with 13C or/and 15N such that cross peaks between 13CO(i-1) and 15NH(i) result only for pairs of sequentially adjacent amino acids. In this way, unambiguous sequence-specific assignments can be obtained for unique pairs of amino acids that occur exactly once in the protein sequence. It is crucial to limit the number of differently labeled protein samples that have to be prepared while obtaining an optimal extent of labeled unique amino acid pairs. The UPLABEL algorithm uses combinatorial optimization to find labeling patterns that maximize the number of unique pair assignments with a minimal number of samples. Various auxiliary conditions, such as labeled amino acid availability and price, previously known partial assignments and sequence regions of particular interest, can be taken into account when determining optimal amino acid type-specific labeling patterns. Usage of the UPLABEL software as implemented in the webportal is free to use (software License by Peter Güntert).
Select the amino acid residue(s) which should not be included into the labeling scheme :