9.B.73 The Chloroplast Envelope/Cyanobacterial Membrane Protein (CemA) Family

The CemA family may be involved in H+ extrusion and thereby indirectly promote HCO3- or CO2 uptake into chloroplasts (Rolland et al., 1997). Ycf10 of C. reinhardtii resembles CotA of the cyanobacterium. Synechocystis (440 aas) involved to CO2 uptake and H+ extrusion. It shows limited sequence similarity with CorC (9.B.37.2.1). Both proteins exhibit 4 or 5 putative TMSs, but CorC has them at the N-terminus of a 410 aa protein while Ycf10 has 3 at its C-terminus.

This family belongs to the .



Katoh, A., K.S. Lee, H. Fukuzawa, K. Ohyama, and T. Ogawa. (1996). cemA homologue essential to CO2 transport in the cyanobacterium Synechocystis PCC6803. Proc. Natl. Acad. Sci. USA 93: 4006-4010.

Rolland, N., A.J. Dorne, G. Amoroso, D.F. Sultemeyer, J. Joyard, and J.D. Rochaix. (1997). Disruption of the plastid ycf10 open reading frame affects uptake of inorganic carbon in the chloroplast of Chlamydomonas. EMBO J. 16: 6713-6726.


TC#NameOrganismal TypeExample
9.B.73.1.1Ycf10 (inner chloroplast membrane; 500 aas; 5 TMSs at residue positions 40, 125, 370, 400, and 450)AlgaeCyf10 of Chlamydomonas reinhardtii (Q37050)
9.B.73.1.2Putative transporter involved in H+ extrusion and indirectly CO2 uptake, CotA. The 3 TMS hydrophobic domain belongs to the CDD CemA family. CotA may be a heme binding protein (Katoh et al., 1996). CyanobacteriaCotA or PcxA of Synechocystis PCC6803 (P75028)