TY  - JOUR
AU  - Macorano, Luis
AU  - Binny, Taniya M.
AU  - Spiegl, Tobias
AU  - Klimenko, Victoria
AU  - Singer, Anna
AU  - Oberleitner, Linda
AU  - Applegate, Violetta
AU  - Seyffert, Sarah
AU  - Stefanski, Anja
AU  - Gremer, Lothar
AU  - Gertzen, Christoph G. W.
AU  - Höppner, Astrid
AU  - Smits, Sander H. J.
AU  - Nowack, Eva C. M.
TI  - DNA-binding and protein structure of nuclear factors likely acting in genetic information processing in the Paulinella chromatophore
JO  - Proceedings of the National Academy of Sciences of the United States of America
VL  - 120
IS  - 27
SN  - 0027-8424
CY  - Washington, DC
PB  - National Acad. of Sciences
M1  - FZJ-2023-03522
SP  - e2221595120
PY  - 2023
AB  - The chromatophores in Paulinella are evolutionary-early-stage photosynthetic organelles. Biological processes in chromatophores depend on a combination of chromatophore and nucleus-encoded proteins. Interestingly, besides proteins carrying chromatophore-targeting signals, a large arsenal of short chromatophore-targeted proteins (sCTPs; <90 amino acids) without recognizable targeting signals were found in chromatophores. This situation resembles endosymbionts in plants and insects that are manipulated by host-derived antimicrobial peptides. Previously, we identified an expanded family of sCTPs of unknown function, named here "DNA-binding (DB)-sCTPs". DB-sCTPs contain a ~45 amino acid motif that is conserved in some bacterial proteins with predicted functions in DNA processing. Here, we explored antimicrobial activity, DNA-binding capacity, and structures of three purified recombinant DB-sCTPs. All three proteins exhibited antimicrobial activity against bacteria involving membrane permeabilization, and bound to bacterial lipids in vitro. A combination of in vitro assays demonstrated binding of recombinant DB-sCTPs to chromatophore-derived genomic DNA sequences with an affinity in the low nM range. Additionally, we report the 1.2 Å crystal structure of one DB-sCTP. In silico docking studies suggest that helix α2 inserts into the DNA major grove and the exposed residues, that are highly variable between different DB-sCTPs, confer interaction with the DNA bases. Identification of photosystem II subunit CP43 as a potential interaction partner of one DB-sCTP, suggests DB-sCTPs to be involved in more complex regulatory mechanisms. We hypothesize that membrane binding of DB-sCTPs is related to their import into chromatophores. Once inside, they interact with the chromatophore genome potentially providing nuclear control over genetic information processing.
LB  - PUB:(DE-HGF)16
C6  - 37364116
UR  - <Go to ISI:>//WOS:001041172600005
DO  - DOI:10.1073/pnas.2221595120
UR  - https://juser.fz-juelich.de/record/1014978
ER  -