Send to

Choose Destination
Protein Sci. 2015 Jul;24(7):1075-86. doi: 10.1002/pro.2689. Epub 2015 Jun 16.

ChSeq: A database of chameleon sequences.

Author information

Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, Texas, 75390-9050.
Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas, 75390-9050.
Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas, 75390-9050.
Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon, 97331.


Chameleon sequences (ChSeqs) refer to sequence strings of identical amino acids that can adopt different conformations in protein structures. Researchers have detected and studied ChSeqs to understand the interplay between local and global interactions in protein structure formation. The different secondary structures adopted by one ChSeq challenge sequence-based secondary structure predictors. With increasing numbers of available Protein Data Bank structures, we here identify a large set of ChSeqs ranging from 6 to 10 residues in length. The homologous ChSeqs discovered highlight the structural plasticity involved in biological function. When compared with previous studies, the set of unrelated ChSeqs found represents an about 20-fold increase in the number of detected sequences, as well as an increase in the longest ChSeq length from 8 to 10 residues. We applied secondary structure predictors on our ChSeqs and found that methods based on a sequence profile outperformed methods based on a single sequence. For the unrelated ChSeqs, the evolutionary information provided by the sequence profile typically allows successful prediction of the prevailing secondary structure adopted in each protein family. Our dataset will facilitate future studies of ChSeqs, as well as interpretations of the interplay between local and nonlocal interactions. A user-friendly web interface for this ChSeq database is available at


ChSeq; biological function; chameleon sequence; conformational change; secondary structure; secondary structure prediction; sequence profile; structural plasticity

[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Wiley Icon for PubMed Central
Loading ...
Support Center