Complete Amino Acid Sequence of Luffin-a, a Ribosome-inactivating Protein from the Seeds of Sponge Gourd (<i>Luffa cylindrica</i>)

Islam, M. Rafiqul; Nishida, Hiromi; Funatsu, Gunki

doi:10.1080/00021369.1990.10870410

Cited by 4 publications

(7 citation statements)

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“…Luffin-a is a type I RIP isolated from Luffa cylindrica seeds (Islam et al, 1990), It is composed of 248 amino acids and has also been found to have RNA N-glycosidase activity. The amino acid sequence of luffin-a has more than 60% homology with that of trichosanthin (TCS) and amomorcharin (oL-MMC), for which the crystal structures have been reported (Ren et al, 1994;Gao et al, 1993).…”

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confidence: 99%

Modeling of the three-dimensional structure of luffin-α and its simulated reaction with the substrate oligoribonucleotide GAGA

et al. 1996

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A fundamental problem in biochemistry and molecular biology is understanding the spatial structure of macromolecules and then analyzing their functions. In this study, the three-dimensional structure of a ribosome-inactivating protein luffin-alpha was predicted using a neural network method and molecular dynamics simulation. A feedforward neural network with the backpropagation learning algorithm were trained on model class of homologous proteins including trichosanthin and alpha-momorcharin. The distance constraints for the C alpha atoms in the protein backbone were utilized to generate a folded crude conformation of luffin-alpha by model building and the steepest descent minimization approach. The crude conformation was refined by molecular dynamics techniques and a simulated annealing procedure. The interaction between luffin-alpha and its analogous substrate GAGA was also simulated to understand its action mechanism.

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Section: Introductionmentioning

confidence: 99%

Modeling of the three-dimensional structure of luffin-α and its simulated reaction with the substrate oligoribonucleotide GAGA

et al. 1996

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“…RIPs attract the interest of many researchers for their possible usage as therapeutic agents, especially against human immunodeficiency virus [ 11,13]. Luffin-a and luffin-b are single-chain RIPs isolated from the seeds of Luffa cylindrica (sponge gourd) [6,9], and their amino acid sequences have been reported [4,5].We have isolated two types of cDNAs for luffin from the cDNA library of the immature seeds of L. cylindrica using PCR-derived probe synthesized on the basis of the amino acid sequence of luffin-a [7]. One contained the same restriction fragment patterns with the probe and encoded c~-luffin, a protein highly homologous to luffin-a [7].…”

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Nucleotide sequence of cDNA encoding ?-luffin, another ribosome-inactivating protein from Luffa cylindrica

et al. 1992

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Many, and possibly all, plants contain ribosomeinactivating proteins (RIPs) [1]. RIPs cleave the N-glycosidic bond at adenine 4324 of rat liver 28S rRNA to inactivate the ribosomes, resulting in the inhibition of protein synthesis [2,12]. RIPs attract the interest of many researchers for their possible usage as therapeutic agents, especially against human immunodeficiency virus [ 11,13]. Luffin-a and luffin-b are single-chain RIPs isolated from the seeds of Luffa cylindrica (sponge gourd) [6,9], and their amino acid sequences have been reported [4,5].We have isolated two types of cDNAs for luffin from the cDNA library of the immature seeds of L. cylindrica using PCR-derived probe synthesized on the basis of the amino acid sequence of luffin-a [7]. One contained the same restriction fragment patterns with the probe and encoded c~-luffin, a protein highly homologous to luffin-a [7]. Here we report a nucleotide sequence of another cDNA which hybridized to the probe but contained Eco RI site not found in the probe. The cDNA was composed of 914 nucleotides containing an open reading frame of 278 amino acid residues ( Fig. 1). Its 5'-non-coding region, 5'-GGGAAAA-3', was almost identical to that of e-luffin, 5'-GGGAAAG-3'. Comparing its 3'-non-coding region to that of c~-luffin, it seems to be truncated by a polyadenylation site different from e-luffin. The protein deduced from the cDNA was designated as fi-luffin. From the alignment of the amino acid sequences of fi-luffin, c~-luffin and luffin-b, fi-luffin seems to be a preproprotein with a secretory signal peptide of 21 residues and an extrapeptide of 10 residues at the NH2 and COOH terminals, respectively (Fig. 1).The amino acid sequence offi-luffin was aligned with those of luffin-a [4], luffin-b [5], and 0~-luffin [7] (Fig. 2). It has been reported that several conserved amino acid residues among many RIPs are involved in forming or stabilizing a putative active cleft of ricin A-chain [8]. Most of them are also conserved among all the luffins (Fig. 2). Mature fl-luffin is more homologous to luffin-b (91 ~o homology) than luffin-a (80 ~o ) and mature c~-luffin (83 ~o), while mature e-luffin is more homologous to luffin-a (96~o) than luffin-b (80~o). These data suggest that the small differences between ~-luffin The nucleotide sequence data reported will appear in the EMBL, GenBank and DDBJ Nucleotide Sequence Databases under the accession number X62372. ~. 1. Nucleotide sequence of the cDNA encoding fi-luffin ~d its deduced amino acid sequence. Isolation of the poly(A) + RNA ~d construction of the cDNA librau ~e described in our previous paper [7]. The cDNAs were isolated from the librwy by plaque hybridization using the PCR-derived probe [7]. Their nucleotide sequences were determined using T7 sequencing kit (Phwmacia). Closed and open ~rowheads indicate putative processing sites at NH 2 and COOH terminals from the Nignment of the amino acid sequences of fi-l~n, ~-luffin mid luffin-b. and luffin-a and those between/Muffin and luffinb in their amino acid sequences...

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Balsamin, a novel ribosome-inactivating protein from the seeds of Balsam apple Momordica balsamina

et al. 2011

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Plant seeds, a rich source of proteins, are considered important for their application as functional ingredients in a food system. A novel ribosome-inactivating protein (RIP), balsamin was purified from the seeds of Balsam apple, Momordica balsamina. Balsamin was purified by ion exchange chromatography on CM Sepharose and gel filtration on superdex-75. It has a molecular weight of 28 kDa as shown by SDS-PAGE analysis. Balsamin inhibits protein synthesis in a rabbit reticulocyte lysate-based cell free translation assay with an IC(50) of 90.6 ng ml(-1). It has RNA N-glycosidase activity and releases a 400-base long fragment termed the Endo fragment from 28S rRNA in the same manner as does saporin-6 from Saponaria officinalis. The N-terminal sequence analysis of the first 12 amino acids of balsamin revealed that it shares 83% similarity with type I RIP α-MMC from Momordica charantia and 50% similarity with β-MMC (from Momordica charantia), bryodin I (from Bryonia dioica) and luffin a (from Luffa cylindrica). Balsamin was further characterized by mass spectrometry. CD spectroscopic studies indicate that secondary structure of balsamin contains helix (23.5%), β-strand (24.6%), turn (20%) and random coil (31.9%). Thus RIPs activity expressed in vegetables like Momordica sp. advocates its usage in diet.

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Complete Amino Acid Sequence of Luffin-a, a Ribosome-inactivating Protein from the Seeds of Sponge Gourd (Luffa cylindrica)

Cited by 4 publications

References 7 publications

Modeling of the three-dimensional structure of luffin-α and its simulated reaction with the substrate oligoribonucleotide GAGA

Modeling of the three-dimensional structure of luffin-α and its simulated reaction with the substrate oligoribonucleotide GAGA

Nucleotide sequence of cDNA encoding ?-luffin, another ribosome-inactivating protein from Luffa cylindrica

Balsamin, a novel ribosome-inactivating protein from the seeds of Balsam apple Momordica balsamina

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