Leucine-rich repeats (LRRs) occur in tandem and the repeat unit lengths (RULs) in general range from 20 to 29 residues. Seven LRR classes have been recognized. A comprehensive sequence analysis of viral LRRs has been done. Most proteins are from nucleocytoplasmic large dsDNA viruses (NCLDVs). The RULs of several LRR types are one to five residues shorter than those of the known, corresponding LRR types. Surprisingly, the RUL of 19 residues which is the shortest among all LRRs are identified in some LRR types. Unique LRR motifs are also observed. The present findings provide a new perspective on the origin and evolution of LRRs.
Dr. Norio Matsushima is Professor Emeritus of Sapporo Medical University. He received his Ph.D. in polymer physics at Hokkaido University in 1976. He joined Sapporo Medical University from 1983. In 1986-1988 he joined the University of Virginia, USA. He studied the structure and evolution of protein tandem repeats including leucine-rich repeats and also developed the HEFIT program for fitting helices. He has published over 100 papers in peer reviewed journals and a book. He is the editorial board member of “Protein and Peptide Letters”.