Journal article

Publication year: 1990

Pages: 7131-7137

Journal: Journal of Bacteriology

Volume number: 172

Issue number: 12

ISSN: 0021-9193

DOI Link: https://doi.org/10.1128/jb.172.12.7131-7137.1990

Publisher: American Society for Microbiology

Abstract: 

Light-harvesting complex I (LHI) of Rhodobacter capsulatus contains
bacteriochlorophyll and carotenoids which are noncovalently bound to two
different apoproteins (alpha and beta polypeptides) carrying oppositely
charged N-terminal ends. The contribution of these charged segments to
the assembly of LHI was studied with mutants having oppositely charged
amino acids in the alpha or beta polypeptide. The influence of these
mutations on the insertion and assembly process of the LHI complex was
investigated by means of spectroscopic analysis of isolated
intracytoplasmic membranes and pulse-chase experiments. Exchange of four
positively charged amino acids to negatively charged amino acids on the
N-terminal domain of the alpha subunit inhibited completely the
assembly of the LHI complex. Although this mutant has no antenna, the
reaction center is active and the cells were able to grow anaerobically
in the light. Conversely, mutation of the four negatively charged amino
acids of the N-terminal segment of the beta polypeptide did not prevent
the assembly of the LHI complex, although the stability of the complex
and the size of the photosynthetic unit were affected. The presence of
the mutated beta polypeptide was confirmed by protein sequencing.

Harvard Citation style: Stiehle, H., Cortez, N., Klug, G. and Drews, G. (1990) A negatively charged N terminus in the alpha polypeptide inhibits formation of light-harvesting complex I in Rhodobacter capsulatus, Journal of Bacteriology, 172(12), pp. 7131-7137. https://doi.org/10.1128/jb.172.12.7131-7137.1990

APA Citation style: Stiehle, H., Cortez, N., Klug, G., & Drews, G. (1990). A negatively charged N terminus in the alpha polypeptide inhibits formation of light-harvesting complex I in Rhodobacter capsulatus. Journal of Bacteriology. 172(12), 7131-7137. https://doi.org/10.1128/jb.172.12.7131-7137.1990