Microalgae and cyanobacteria contribute roughly half of the global photosynthetic carbon assimilation. Faced with limited access to CO2in aquatic environments, which can vary daily or hourly, these microorganisms have evolved use of an efficient CO2concentrating mechanism (CCM) to accumulate high internal concentrations of inorganic carbon (Ci) to maintain photosynthetic performance. For eukaryotic algae, a combination of molecular, genetic and physiological studies using the model organism
- Award ID(s):
- 1710175
- NSF-PAR ID:
- 10057152
- Date Published:
- Journal Name:
- The Analyst
- Volume:
- 142
- Issue:
- 21
- ISSN:
- 0003-2654
- Page Range / eLocation ID:
- 4089 to 4098
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Chlamydomonas reinhardtii , have revealed the function and molecular characteristics of many CCM components, including active Ciuptake systems. Fundamental to eukaryotic Ciuptake systems are Citransporters/channels located in membranes of various cell compartments, which together facilitate the movement of Cifrom the environment into the chloroplast, where primary CO2assimilation occurs. Two putative plasma membrane Citransporters, HLA3 and LCI1, are reportedly involved in active Ciuptake. Based on previous studies, HLA3 clearly plays a meaningful role in HCO3−transport, but the function of LCI1 has not yet been thoroughly investigated so remains somewhat obscure. Here we report a crystal structure of the full‐length LCI1 membrane protein to reveal LCI1 structural characteristics, as well asin vivo physiological studies in an LCI1 loss‐of‐function mutant to reveal the Cispecies preference for LCI1. Together, these new studies demonstrate LCI1 plays an important role in active CO2uptake and that LCI1 likely functions as a plasma membrane CO2channel, possibly a gated channel. -
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