Evidence that two ATP-dependent (Lon) proteases in Borrelia burgdorferi serve different functions
The canonical ATP-dependent protease Lon participates in an assortment of biological processes in bacteria, including the catalysis of damaged or senescent proteins and short-lived regulatory proteins. Borrelia spirochetes are unusual in that they code for two putative ATP-dependent Lon homologs, Lo...
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Published in | PLoS pathogens Vol. 5; no. 11; p. e1000676 |
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Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
Public Library of Science
01.11.2009
Public Library of Science (PLoS) |
Subjects | |
Online Access | Get full text |
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Summary: | The canonical ATP-dependent protease Lon participates in an assortment of biological processes in bacteria, including the catalysis of damaged or senescent proteins and short-lived regulatory proteins. Borrelia spirochetes are unusual in that they code for two putative ATP-dependent Lon homologs, Lon-1 and Lon-2. Borrelia burgdorferi, the etiologic agent of Lyme disease, is transmitted through the blood feeding of Ixodes ticks. Previous work in our laboratory reported that B. burgdorferi lon-1 is upregulated transcriptionally by exposure to blood in vitro, while lon-2 is not. Because blood induction of Lon-1 may be of importance in the regulation of virulence factors critical for spirochete transmission, the clarification of functional roles for these two proteases in B. burgdorferi was the object of this study. On the chromosome, lon-2 is immediately downstream of ATP-dependent proteases clpP and clpX, an arrangement identical to that of lon of Escherichia coli. Phylogenetic analysis revealed that Lon-1 and Lon-2 cluster separately due to differences in the NH(2)-terminal substrate binding domains that may reflect differences in substrate specificity. Recombinant Lon-1 manifested properties of an ATP-dependent chaperone-protease in vitro but did not complement an E. coli Lon mutant, while Lon-2 corrected two characteristic Lon-mutant phenotypes. We conclude that B. burgdorferi Lons -1 and -2 have distinct functional roles. Lon-2 functions in a manner consistent with canonical Lon, engaged in cellular homeostasis. Lon-1, by virtue of its blood induction, and as a unique feature of the Borreliae, may be important in host adaptation from the arthropod to a warm-blooded host. |
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Bibliography: | ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 ObjectType-Article-1 ObjectType-Feature-2 Conceived and designed the experiments: JLC LIK AT NAO JLB. Performed the experiments: JLC LIK CK AT NAO. Analyzed the data: JLC LIK CK AT NAO RT. Contributed reagents/materials/analysis tools: RT. Wrote the paper: JLC LIK JLB. |
ISSN: | 1553-7374 1553-7366 1553-7374 |
DOI: | 10.1371/journal.ppat.1000676 |