Structure of antibacterial peptide microcin J25: a 21-residue lariat protoknot.
The antibacterial peptide microcin J25 (MccJ25) inhibits bacterial transcription by binding within, and obstructing, the nucleotide-uptake channel of bacterial RNA polymerase. Published covalent and three-dimensional structures indicate that MccJ25 is a 21-residue cycle. Here, we show that the published covalent and three-dimensional structures are incorrect, and that MccJ25 in fact is a 21-residue "lariat protoknot", consisting of an 8-residue cyclic segment followed by a 13-residue linear segment that loops back and threads through the cyclic segment. MccJ25 is the first example of a lariat protoknot involving a backbone-side chain amide linkage.
Bayro
Marvin J
MJ
Department of Molecular Biology and Biochemistry, Waksman Institute, and Howard Hughes Medical Institute, Rutgers University, Piscataway, New Jersey 08854, USA.
Mukhopadhyay
Jayanta
J
Swapna
G V T
GV
Huang
Janet Y
JY
Ma
Li-Chung
LC
Sineva
Elena
E
Dawson
Philip E
PE
Montelione
Gaetano T
GT
Ebright
Richard H
RH
D000900:Anti-Bacterial Agents / Q000737:chemistry; D001430:Bacteriocins / Q000737:chemistry*; D008958:Models, Molecular; D010455:Peptides; D011487:Protein Conformation; D021241:Spectrometry, Mass, Electrospray Ionization
D000900:Anti-Bacterial Agents; D001430:Bacteriocins; D010455:Peptides; C020411:microcin