Structure/function studies on two type 1 ribosome inactivating proteins: Bouganin and lychnin.
The three-dimensional structures of two type 1 RIPs, bouganin and lychnin, has been solved. Their adenine polynucleotide glycosylase activity was also determined together with other known RIPs: dianthin 30, PAP-R, momordin I, ricin A chain and saporin-S6. Saporin-S6 releases the highest number of adenine molecules from rat ribosomes, and poly(A), while its efficiency is similar to dianthin 30, bouganin and PAP-R on herring sperm DNA. Measures of the protein synthesis inhibitory activity confirmed that saporin-S6 is the most active. The overall structure of bouganin and lychnin is similar to the other considered RIPs and the typical RIP fold is conserved. The superimpositioning of their C(alpha) atoms highlights some differences in the N-terminal and C-terminal domains. A detailed structural analysis indicates that the efficiency of saporin-S6 on various polynucleotides can be ascribed to a negative electrostatic surface potential at the active site and several exposed positively charged residues in the region around that site. These two conditions, not present at the same time in other examined RIPs, could guarantee an efficient interaction with the substrate and an efficient catalysis.
Fermani
Simona
S
Department of Chemistry "G. Ciamician", Alma Mater Studiorum University of Bologna, Italy. simona.fermani@unibo.it
Tosi
Giovanna
G
Farini
Valentina
V
Polito
Letizia
L
Falini
Giuseppe
G
Ripamonti
Alberto
A
Barbieri
Luigi
L
Chambery
Angela
A
Bolognesi
Andrea
A
D000595:Amino Acid Sequence; D000818:Animals; D018360:Crystallography, X-Ray; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D051381:Rats; D054788:Ribosome Inactivating Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D054789:Ribosome Inactivating Proteins, Type 1 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D013329:Structure-Activity Relationship
D054789:Ribosome Inactivating Proteins, Type 1; C525537:lychnin; D054788:Ribosome Inactivating Proteins