RT Journal Article
T1 The Parasporal Body of Bacillus thuringiensis subsp. israelensis: A Unique Phage Capsid-Associated Prokaryotic Insecticidal Organelle
A1 Rudd, Sarah
A1 Miranda, Leticia Silva
A1 Curtis, Hannah
A1 Bigot, Yves
A1 Díaz Mendoza, María Mercedes
A1 Hice, Robert
A1 Nizet, Victor
A1 Park, Hyun-Woo
A1 Blaha, Gregor
A1 Federici, Brian
A1 Bideshi, Dennis
AB The three most important commercial bacterial insecticides are all derived from subspecies of Bacillus thuringiensis (Bt). Specifically, Bt subsp. kurstaki (Btk) and Bt subsp. aizawai (Bta) are used to control larval lepidopteran pests. The third, Bt subsp. israelensis (Bti), is primarily used to control mosquito and blackfly larvae. All three subspecies produce a parasporal body (PB) during sporulation. The PB is composed of insecticidal proteins that damage the midgut epithelium, initiating a complex process that results in the death of the insect. Among these three subspecies of Bt, Bti is unique as it produces the most complex PB consisting of three compartments. Each compartment is bound by a multilaminar fibrous matrix (MFM). Two compartments contain one protein each, Cry11Aa1 and Cyt1Aa1, while the third contains two, Cry4Aa1/Cry4Ba1. Each compartment is packaged independently before coalescing into the mature spherical PB held together by additional layers of the MFM. This distinctive packaging process is unparalleled among known bacterial organelles, although the underlying molecular biology is yet to be determined. Here, we present structural and molecular evidence that the MFM has a hexagonal pattern to which Bti proteins Bt152 and Bt075 bind. Bt152 binds to a defined spot on the MFM during the development of each compartment, yet its function remains unknown. Bt075 appears to be derived from a bacteriophage major capsid protein (MCP), and though its sequence has markedly diverged, it shares striking 3-D structural similarity to the Escherichia coli phage HK97 Head 1 capsid protein. Both proteins are encoded on Bti’s pBtoxis plasmid. Additionally, we have also identified a six-amino acid motif that appears to be part of a novel molecular process responsible for targeting the Cry and Cyt proteins to their cytoplasmic compartments. This paper describes several previously unknown features of the Bti organelle, representing a first step to understanding the biology of a unique process of sorting and packaging of proteins into PBs. The insights from this research suggest a potential for future applications in nanotechnology.
PB MDPI
SN 2079-7737
YR 2023
FD 2023
LK https://hdl.handle.net/20.500.14352/94122
UL https://hdl.handle.net/20.500.14352/94122
LA eng
NO Rudd, S.R.; Miranda, L.S.; Curtis, H.R.; Bigot, Y.; Diaz-Mendoza, M.; Hice, R.; Nizet, V.; Park, H.-W.; Blaha, G.; Federici, B.A.; et al. The Parasporal Body of Bacillus thuringiensis subsp. israelensis: A Unique Phage Capsid-Associated Prokaryotic Insecticidal Organelle. Biology 2023, 12, 1421. https://doi.org/10.3390/biology12111421
NO FondosEsta investigación fue apoyada por una subvención de los Institutos Nacionales de Salud (RO1 AI45817) a BAF y microbecas del Fondo de Desarrollo Docente de la Universidad Bautista de California a DKB y HWP.
NO National Institutes of Health (USA)
NO California Baptist University
DS Docta Complutense
RD 24 abr 2025