title: Cloning, sequence analysis and crystal structure determination of a miraculin-like protein from Murraya koenigii.
abstract: Earlier, the purification of a 21.4kDa protein with trypsin inhibitory activity from seeds of Murraya koenigii has been reported. The present study, based on the amino acid sequence deduced from both cDNA and genomic DNA, establishes it to be a miraculin-like protein and provides crystal structure at 2.9A resolution. The mature protein consists of 190 amino acid residues with seven cysteines arranged in three disulfide bridges. The amino acid sequence showed maximum homology and formed a distinct cluster with miraculin-like proteins, a soybean Kunitz super family member, in phylogenetic analyses. The major differences in sequence were observed at primary and secondary specificity sites in the reactive loop when compared to classical Kunitz family members. The crystal structure analysis showed that the protein is made of twelve antiparallel beta-strands, loops connecting beta-strands and two short helices. Despite similar overall fold, it showed significant differences from classical Kunitz trypsin inhibitors.
authors.affiliation: Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, India.
authors.forename: Deepankar
authors.initials: D
authors.lastname: Gahloth
authors.forename: Purushotham
authors.initials: P
authors.lastname: Selvakumar
authors.forename: Chandan
authors.initials: C
authors.lastname: Shee
authors.forename: Pravindra
authors.initials: P
authors.lastname: Kumar
authors.forename: Ashwani Kumar
authors.initials: AK
authors.lastname: Sharma
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D018360:Crystallography, X-Ray; D018076:DNA, Complementary; D008958:Models, Molecular; D008969:Molecular Sequence Data; D032101:Murraya / Q000737:chemistry*; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics*; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid
chemical_list: D018076:DNA, Complementary; D010940:Plant Proteins