Koherent diffraktionsavbildning och nanokristallografi: Struktur av intakta karboxysomer och komponenter

Tidsperiod: 2011-01-01 till 2015-12-31

Projektledare: Inger Andersson

Finansiär: Vetenskapsrådet

Bidragstyp: Projektbidrag

Budget: 10 000 000 SEK

A grand challenge for the 21st century is to develop a molecular-level understanding of a living cell. A key step in this direction is to obtain structures for individual cell organelles. The structure of the ribosome has now been done. The aim of this proposal is to derive a high-resolution structure for a unique carbon-fixation organelle from photosynthetic picoplankton. Supplies of free CO2 are restricted in the oceans due to slow diffusion rates and high pH values. Phytoplankton have evolved CO2-concentrating mechanisms, using transporters and specialised cell organelles (the carboxysomes) to boost carbon-fixation. As a result, marine CO2-fixation is significantly more efficient than terrestrial carbon fixation, and this has strong environmental implications. Little is known about the 3D structure of carboxysomes. They are believed to contain a Rubisco nanocrystal with carbonic anhydrase molecules enclosed in a virus-like protein shell. Biochemical studies on isolated carboxysomes and carboxysomal proteins are performed at SLU. Our goal in this proposal is to join forces with CFEL, FLASH, PETRA III and XFEL to obtain 3D structures for intact carboxysomes by coherent diffractive imaging. Our recent results on imaging single virus particles and protein nanocrystals show this approach is feasible. The work will guide developments in coherent X-ray imaging, and will have an impact on cell biology, agriculture, the environmental sciences and geochemistry.