@article {Niederhuber086090, author = {Matthew J. Niederhuber and Talley J. Lambert and Clarence Yapp and Pamela A. Silver and Jessica K. Polka}, title = {Super-resolution microscopy of the {\ss}-carboxysome reveals a homogenous matrix}, elocation-id = {086090}, year = {2016}, doi = {10.1101/086090}, publisher = {Cold Spring Harbor Laboratory}, abstract = {Carbon fixation in cyanobacteria makes a major contribution to the global carbon cycle. The cyanobacterial carboxysome is a proteinaceous microcompartment that protects and concentrates the carbon-fixing enzyme RuBisCO in a paracrystalline lattice, making it possible for these organisms to fix CO2 from the atmosphere. The protein responsible for the organization of this lattice in beta-type carboxysomes of the freshwater cyanobacterium Synechococcus elongatus, CcmM, occurs in two isoforms thought to localize differentially within the carboxysome matrix. Here, we use widefield timelapse and 3D-structured illumination microscopy (3D-SIM) to study the recruitment and localization of these two isoforms. We demonstrate that this super-resolution technique is capable of successfully resolving the outer protein shell of the carboxysome from its internal cargo. We develop an automated analysis pipeline to analyze and quantify 3D-SIM images and generate a population level description of carboxysome shell protein, RuBisCO, and CcmM isoform localization. We find that both CcmM isoforms colocalize in space and time, prompting a revised model of the internal arrangement of the beta carboxysome.}, URL = {https://www.biorxiv.org/content/early/2016/11/23/086090}, eprint = {https://www.biorxiv.org/content/early/2016/11/23/086090.full.pdf}, journal = {bioRxiv} }