(v) Photosystem function and regulation

We are aiming to explore electron transfer and binding mechanisms between the soluble electron transfer proteins plastocyanin or cytochrome c6 and photosystem I (PSI) (Finazzi et al., 2005; Sommer et al., 2004; Sommer et al., 2006; Sommer et al., 2002, Kuhlgert et al., 2012). Additionally, we aim to investigate the molecular recognition between PSI and its light-harvesting protein complex (LHCI), allowing the formation of the PSI/LHCI complex, subunit remodeling as well as efficient excitation energy transfer (Naumann et al., 2005; Nield et al., 2004; Storf et al., 2004; Takahashi et al., 2004, Busch et al., 2010). Hereby we are also taking advantage of absolute quantitation by using proteotypic peptide probes to enumerate the stoichiometry of LHCI subunits per PSI core complex (Stauber et al., 2009) as well as chemical crosslinking and mass spectrometric peptide identification (Ozawa et al., 2018). For structural analysis of PSI-LHCI complexes we using single particle electron microscopy (Steinbeck et al., 2018) and cryo-electron microscopy (unpublished). We are also engaged in characterizing LHCSR3 photosystem association and phosphorylation (Xue et al., 2015, Scholz et al., 2019).

Scholz M, Gabelein P, Xue H, Mosebach L, Bergner SV, Hippler M (2019)
Light-dependent N-terminal phosphorylation of LHCSR3 and LHCB4 are interlinked in Chlamydomonas reinhardtii.
Plant J 99: 877-894

Steinbeck J, Ross IL, Rothnagel R, Gabelein P, Schulze S, Giles N, Ali R, Drysdale R, Sierecki E, Gambin Y, Stahlberg H, Takahashi Y, Hippler M, Hankamer B (2018)
Structure of a PSI-LHCI-cyt b6f supercomplex in Chlamydomonas reinhardtii promoting cyclic electron flow under anaerobic conditions.
Proc Natl Acad Sci U S A 115: 10517-10522

Ozawa SI, Bald T, Onishi T, Xue H, Matsumura T, Kubo R, Takahashi H, Hippler M, Takahashi Y (2018)
Configuration of Ten Light-Harvesting Chlorophyll a/b Complex I Subunits in Chlamydomonas reinhardtii Photosystem I.
Plant Physiol 178: 583-595

Xue H, Tokutsu R, Bergner SV, Scholz M, Minagawa J, Hippler M (2015)
PHOTOSYSTEM II SUBUNIT R is required for efficient binding of LIGHT-HARVESTING COMPLEX STRESS-RELATED PROTEIN3 to photosystem II-light-harvesting supercomplexes in Chlamydomonas reinhardtii.
Plant physiology 167: 1566-78

Busch A, Nield J, Hippler M (2010)
The composition and structure of photosystem I-associated antenna from Cyanidioschyzon merolae.
Plant J 62: 886-97

Stauber EJ, Busch A, Naumann B, Svatos A, Hippler M (2009)
Proteotypic profiling of LHCI from Chlamydomonas reinhardtii provides new insights into structure and function of the complex.
Proteomics 9: 398-408

Sommer F, Drepper F, Haehnel W, Hippler M (2006)
Identification of Precise Electrostatic Recognition Sites between Cytochrome c6 and the Photosystem I Subunit PsaF Using Mass Spectrometry.
J Biol Chem 281: 35097-103

Naumann B, Stauber EJ, Busch A, Sommer F, Hippler M (2005)
N-terminal processing of Lhca3 Is a key step in remodeling of the photosystem I-light-harvesting complex under iron deficiency in Chlamydomonas reinhardtii.
J Biol Chem 280: 20431-41

Finazzi G, Sommer F, Hippler M (2005)
Release of oxidized plastocyanin from photosystem I limits electron transfer between photosystem I and cytochrome b6f complex in vivo.
Proc Natl Acad Sci U S A 102: 7031-6

Sommer F, Drepper F, Haehnel W, Hippler M (2004)
The hydrophobic recognition site formed by residues PsaA-Trp651 and PsaB-Trp627 of photosystem I in Chlamydomonas reinhardtii confers distinct selectivity for binding of plastocyanin and cytochrome c6.
J Biol Chem 279: 20009-17

Storf S, Stauber EJ, Hippler M, Schmid VH (2004)
Proteomic analysis of the photosystem I light-harvesting antenna in tomato (Lycopersicon esculentum).
Biochemistry 43: 9214-24

Takahashi Y, Yasui TA, Stauber EJ, Hippler M (2004)
Comparison of the subunit compositions of the PSI-LHCI supercomplex and the LHCI in the green alga Chlamydomonas reinhardtii.
Biochemistry 43: 7816-23

Nield J, Redding K, Hippler M (2004)
Remodeling of light-harvesting protein complexes in chlamydomonas in response to environmental changes.
Eukaryot Cell 3: 1370-80

Sommer F, Drepper F, Hippler M (2002)
The luminal helix l of PsaB is essential for recognition of plastocyanin or cytochrome c6 and fast electron transfer to photosystem I in Chlamydomonas reinhardtii.
J Biol Chem 277: 6573-81