| Autor: |
Maria Ines Gimenez, Mechthild Pohlschroder, Kieran Dilks |
| Rok vydání: |
2007 |
| Předmět: |
|
| Zdroj: |
Molecular Microbiology. 66:1597-1606 |
| ISSN: |
0950-382X |
| DOI: |
10.1111/j.1365-2958.2007.06034.x |
| Popis: |
Summary Recent in silico and in vivo studies have suggested that the majority of proteins destined for secretion in the haloarchaea are trafficked through the twin- arginine translocation (Tat) pathway. The presence of lipobox motifs in most haloarchaeal Tat signal sequences is intriguing as: (i) bioinformatic searches of archaeal genomes have not identified lipoprotein biogenesis enzymes and (ii) there are no known Tat substrates containing both a twin-arginine and a bona fide lipobox. We have examined six computationally designated Tat substrates in the haloarchaeon Halof- erax volcanii to verify previous computational predic- tions and to initiate studies of lipoprotein biogenesis via the Tat pathway. Our results confirmed that the six candidate proteins were not only Tat substrates, but also belonged to diverse classes of secretory proteins. Analysis of predicted lipoprotein Tat substrates revealed that they are anchored to the archaeal membrane in a cysteine-dependent manner. Interestingly, despite the absence of an archaeal lipo- protein signal peptidase II (SPase II) homologue, the SPase II inhibitor globomycin impeded cell growth and specifically prevented maturation of lipoproteins. Together, this work not only represents the first experimental demonstration of a lipoprotein Tat sub- strate, but also indicates the presence of an uniden- tified lipoprotein biogenesis pathway in archaea. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
|
Plný text