Chitin-binding proteins in invertebrates and plants comprise a common chitin-binding structural motif.
Tachycitin, a 73-residue polypeptide having antimicrobial activity is present in the hemocyte of horseshoe crab (Tachypleus tridentatus). The first three-dimensional structure of invertebrate chitin-binding protein was determined for tachycitin using two-dimensional nuclear magnetic resonance spectroscopy. The measurements indicate that the structure of tachycitin is largely divided into N- and C-terminal domains; the former comprises a three-stranded beta-sheet and the latter a two-stranded beta-sheet following a short helical turn. The latter structural motif shares a significant tertiary structural similarity with the chitin-binding domain of plant chitin-binding protein. This result is thought to provide faithful experimental evidence to the recent hypothesis that chitin-binding proteins of invertebrates and plants are correlated by a convergent evolution process.
Suetake
T
T
Division of Biological Sciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan. tsuda@hniri.go.jp
Tsuda
S
S
Kawabata
S
S
Miura
K
K
Iwanaga
S
S
Hikichi
K
K
Nitta
K
K
Kawano
K
K
D000595:Amino Acid Sequence; D000890:Anti-Infective Agents / Q000737:chemistry; D001665:Binding Sites; D001798:Blood Proteins / Q000737:chemistry*; D002352:Carrier Proteins / Q000737:chemistry*; D002686:Chitin / Q000378:metabolism; D016384:Consensus Sequence; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017433:Protein Structure, Secondary
D000890:Anti-Infective Agents; D001798:Blood Proteins; D002352:Carrier Proteins; C104989:tachycitin protein, Tachypleus tridentatus; D002686:Chitin