PARENT SESSION
Posters P8B Supermolecular organization of the photosynthetic apparatus. Abstracts (592-611)

Processing of the Rhodobacter sphaeroides PufX peptide at the C-terminus. Emma Ratcliffe^*,1, Neil Hunter¹, ¹ University of Sheffield, Sheffield, South Yorkshire, United Kingdom

ABSTRACT- PufX is an integral component of the RC-LH1 core complex of Rb. sphaeroides. It is a single transmembrane helical protein with the N-terminus found on the cytoplasmic side of the intracytoplasmic membrane (ICM). The C-terminus of the peptide has not been located but is predicted to be on the periplasmic side of the ICM. Evidence from Parkes-Loach et al. (2001) suggested that the mature PufX protein was 12 amino acids shorter than the deduced protein sequence. To examine this proposition further, PufX was labelled at either the N- or C-terminus with either a T7- and a His6-tag. The resulting gene construct was placed in strains of Rb. sphaeroides that either contained LH2 or were RC-LH1 only. Using antibodies against the tags and PufX it was shown that neither the T7- nor His6-tag could be detected at the C-terminus of the peptide, and this occurred regardless of the presence of LH2. We also present results on the use of moveable T7-tags, which help to locate the processing point at the C-terminus of PufX.

KEY WORDS: rhodobacter sphaeroides, pufx