Dataset Information

CO-sensing mechanisms.

ABSTRACT: Carbon monoxide (CO) has long been known to have dramatic physiological effects on organisms ranging from bacteria to humans, but recently there have a number of suggestions that organisms might have specific sensors for CO. This article reviews the current evidence for a variety of proteins with demonstrated or potential CO-sensing ability. Particular emphasis is placed on the molecular description of CooA, a heme-containing CO sensor from Rhodospirillum rubrum, since its biological role as a CO sensor is clear and we have substantial insight into the basis of its sensing ability.

SUBMITTER: Roberts GP

PROVIDER: S-EPMC515253 | biostudies-literature | 2004 Sep

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

CO-sensing mechanisms.

Roberts Gary P GP Youn Hwan H Kerby Robert L RL

Microbiology and molecular biology reviews : MMBR 20040901 3

Carbon monoxide (CO) has long been known to have dramatic physiological effects on organisms ranging from bacteria to humans, but recently there have a number of suggestions that organisms might have specific sensors for CO. This article reviews the current evidence for a variety of proteins with demonstrated or potential CO-sensing ability. Particular emphasis is placed on the molecular description of CooA, a heme-containing CO sensor from Rhodospirillum rubrum, since its biological role as a C ...[more]

PMID: 15353565

Similar Datasets

Project description:Diatoms are one of the most successful marine eukaryotic algal groups, responsible for up to 20% of the annual global CO2 fixation. The evolution of a CO2-concentrating mechanism (CCM) allowed diatoms to overcome a number of serious constraints on photosynthesis in the marine environment, particularly low [CO2]aq in seawater relative to concentrations required by the CO2 fixing enzyme, ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO), which is partly due to the slow diffusion rate of CO2 in water and a limited CO2 formation rate from [Formula: see text] in seawater. Diatoms use two alternative strategies to take up dissolved inorganic carbon (DIC) from the environment: one primarily relies on the direct uptake of [Formula: see text] through plasma-membrane type solute carrier (SLC) 4 family [Formula: see text] transporters and the other is more reliant on passive diffusion of CO2 formed by an external carbonic anhydrase (CA). Bicarbonate taken up into the cytoplasm is most likely then actively transported into the chloroplast stroma by SLC4-type transporters on the chloroplast membrane system. Bicarbonate in the stroma is converted into CO2 only in close proximity to RubisCO preventing unnecessary CO2 leakage. CAs play significant roles in mobilizing DIC as it is progressively moved towards the site of fixation. However, the evolutionary types and subcellular locations of CAs are not conserved between different diatoms, strongly suggesting that this DIC mobilization strategy likely evolved multiple times with different origins. By contrast, the recent discovery of the thylakoid luminal θ-CA indicates that the strategy to supply CO2 to RubisCO in the pyrenoid may be very similar to that of green algae, and strongly suggests convergent coevolution in CCM function of the thylakoid lumen not only among diatoms but among eukaryotic algae in general. In this review, both experimental and corresponding theoretical models of the diatom CCMs are discussed.This article is part of the themed issue 'The peculiar carbon metabolism in diatoms'.

Project description:Carbon monoxide (CO) is an endogenous signaling molecule with demonstrated pharmacological effects. For studying CO biology, there is a need for sensitive and selective fluorescent probes for CO as research tools. In developing such probes, CO gas and/or commercially available metal-carbonyl-based "CO-releasing molecules" (CORMs) have been used as CO sources. However, new findings are steadily emerging that some of these commonly used CORMs do not release CO reliably in buffers commonly used for studying such CO probes and have very pronounced chemical reactivities of their own, which could lead to the erroneous identification of "CO probes" that merely detect the CORM used, not CO. This is especially true when the CO-sensing mechanism relies on chemistry that is not firmly established otherwise. Cu2+ can quench the fluorescence of an imine-based fluorophore, DPHP, presumably through complexation. The Cu2+-quenched fluorescence was restored through the addition of CORM-3, a Ru-based CORM. This approach was reported as a new "strategy for detecting carbon monoxide" with the proposed mechanism being dependent on CO reduction of Cu2+ to Cu1+ under near-physiological conditions ( Anal. Chem. 2022, 94, 11298-11306). The study only used CORM-3 as the source of CO. CORM-3 has been reported to have very pronounced redox reactivity and is known not to release CO in an aqueous solution unless in the presence of a strong nucleophile. To assess whether the fluorescent response of the DPHP-Cu(II) cocktail to CORM-3 was truly through detecting CO, we report experiments using both pure CO and CORM-3. We confirm the reported DPHP-Cu(II) response to CORM-3 but not pure CO gas. Further, we did not observe the stated selectivity of DPHP for CO over sulfide species. Along this line, we also found that a reducing agent such as ascorbate was able to induce the same fluorescent turn-on as CORM-3 did. As such, the DPHP-Cu(II) system is not a CO probe and cannot be used to study CO biology. Corollary to this finding, it is critical that future work in developing CO probes uses more than a chemically reactive "CO donor" as the CO source. Especially important will be to confirm the ability of the "CO probe" to detect CO using pure CO gas or another source of CO.

Dataset Information

CO-sensing mechanisms.

Publications

CO-sensing mechanisms.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets