Analyses of non-leucine-rich repeat (non-LRR) regions intervening between LRRs in proteins

• Published in: Biochimica et biophysica acta Vol. 1790; no. 10; pp. 1217 - 1237
• Main Authors: Matsushima, Norio, Mikami, Tomoko, Tanaka, Takanori, Miyashita, Hiroki, Yamada, Keiko, Kuroki, Yoshio
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.10.2009
• Subjects: Amino Acid Sequence; Animals; Arabidopsis Proteins - genetics; Bacterial Proteins - genetics; Caenorhabditis elegans Proteins - genetics; Computational Biology - methods; Databases, Protein; Duplication; Fungi adenylate cyclase; Humans; Intrinsically disordered region; Island region; Leishmania proteophosphoglycans; Leucine-rich repeat; Membrane Proteins - genetics; Molecular Sequence Data; Multigene Family - genetics; Proteins - classification; Proteins - genetics; Proteoglycans - genetics; Protozoan Proteins - genetics; Rapid evolution; Repetitive Sequences, Amino Acid; Sequence Homology, Amino Acid; Super motif; LRR@IR; LRRNT; LRRC17; Intrinsically disordered region; Leucine-rich repeat; Leishmania proteophosphoglycans; LRRC32; LRR; BR; CHADL; acy; MDP; Island region; TLR; Rapid evolution; Duplication; ppg; TPBG; LRRCT; IR; PSK; RANGAP1; LRR-RLK; SLRP; HGT; LRR-RLP; LRRC9; HCS; Super motif; LRK-1; VS; Fungi adenylate cyclase
• ISSN: 0304-4165; 0006-3002; 1872-8006
• DOI: 10.1016/j.bbagen.2009.06.014

Many proteins have LRR (leucine-rich repeat) units interrupted by non-LRRs which we call IR (non-LRR island region). We identified proteins containing LRR@IRs (LRRs having IR) by using a new method and then analyzed their natures and distributions. LRR@IR proteins were found in over two hundred proteins from prokaryotes and from eukaryotes. These are divided into twenty-one different protein families. The IRs occur one to four times in LRR regions and range in length from 5 to 11,265 residues. The IR lengths in Fungi adenylate cyclases (acys) range from 5 to 116 residues; there are 22 LRR repeats. The IRs in Leishmania proteophosphoglycans (ppgs) vary from 105 to 11,265 residues. These results indicate that the IRs evolved rapidly. A group of LRR@IR proteins—LRRC17, chondroadherin-like protein, ppgs, and four Pseudomonas proteins—have a super motif consisting of an LRR block and its adjacent LRR@IR region. This indicates that the entire super motif experienced duplication. The sequence analysis of IRs offers functional similarity in some LRR@IR protein families. This study suggests that various IRs and super motifs provide a great variety of structures and functions for LRRs.