Heavy-atom connectivity orientation for L-cysteine. Hydrogens, visually proven stereochemistry, protonation state, measured conformation, metal binding, metabolic fate, concentration, and disease claims are intentionally omitted; this is an educational reconstruction.
Scientific media record5 verified identifiers
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- L-Cysteinehost-defense
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- WikiBiome:cysteinePubChem:5862ChEBI:17561MeSH:D003545InChIKey:XUJNEKJLAYXESH-REOHCLBHSA-N
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- Editorial review completeIdentifiers authority-verified · Accessibility validated · · cysteine|cysteine-host-defense-v1.webp
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Cysteine is a sulfur-containing amino acid whose thiol (-SH) group makes it the primary metal-binding residue in biology. It is the rate-limiting precursor for Glutathione (GSH) (the master intracellular antioxidant), a key residue in metallothioneins (metal-binding proteins), and a precursor for Hydrogen Sulfide (H₂S) (via CBS/CSE enzymes).
In the WikiBiome framework, cysteine sits at the intersection of metal detoxification, antioxidant defense, and microbial sulfur metabolism.
Evidence map3 cited passagesInspect provenance +
Cadmium, mercury, lead, arsenic all bind cysteine thiol groups with high affinity, depleting free cysteine and glutathione pools → oxidative stress.
Iron-sulfur clusters use cysteine ligands—heavy metal disruption of Fe-S clusters is a primary toxicity mechanism.
Nickel: Bacterial nickel-binding proteins (Hpn, HypB) use histidine-rich motifs, but cysteine residues are critical in nickel efflux and storage proteins.
Metal Binding#
Cadmium, mercury, lead, arsenic all bind cysteine thiol groups with high affinity, depleting free cysteine and glutathione pools → Oxidative Stress.[1]Molecular Mechanisms of Cellular Injury and Role of Toxic Heavy Metals in Chronic Kidney DiseaseManish Mishra, Larry Nichols, Aditi A. Dave et al. · 2022Open reference 1 ↓[2]Heavy Metal Pollution in the Environment and Their Toxicological Effects on HumansBriffa J, Sinagra E, Blundell R · 2020Open reference 2 ↓
Zinc-finger proteins use cysteine (and Histidine) residues to coordinate zinc—metal displacement at these sites is the basis of Mis-Metallation.
Iron-sulfur clusters use cysteine ligands—heavy metal disruption of iron (Fe)-S clusters is a primary toxicity mechanism.[3]Effects of Heavy Metals on Gut Barrier Integrity and Gut MicrobiotaSweta Ghosh, Syam P. Nukavarpu, Venkatakrishna Rao Jala · 2024Open reference 3 ↓
Nickel: Bacterial nickel-binding proteins (Hpn, HypB) use histidine-rich motifs, but cysteine residues are critical in nickel efflux and storage proteins.[4]Role of Nickel in Microbial PathogenesisRobert J. Maier, Stéphane L. Benoit · 2019Open reference 4 ↓
Microbial Context#
Gut bacteria metabolize dietary cysteine via desulfhydrase enzymes → H₂S production (Hydrogen Sulfide (H₂S)). Microbial cysteine metabolism affects the gut sulfur pool, influencing both host detoxification capacity and Desulfovibrio ecology.
Cross-References#
- Glutathione (GSH)—cysteine is the rate-limiting precursor
- Hydrogen Sulfide (H₂S)—cysteine as H₂S precursor
- Mis-Metallation—metal displacement at cysteine-coordinated sites
- Iron—iron-sulfur cluster cysteine ligands
- Cadmium—high-affinity cysteine thiol binding
- oxidative stress—cysteine depletion reduces antioxidant capacity
References 4
Numbered by first appearance in the article, then reconciled with its declared source list.
- 1
★Manish Mishra, Larry Nichols, Aditi A. Dave et al. (2022). Molecular Mechanisms of Cellular Injury and Role of Toxic Heavy Metals in Chronic Kidney Disease. International Journal of Molecular Sciences.
- 2
Briffa J, Sinagra E, Blundell R (2020). Heavy Metal Pollution in the Environment and Their Toxicological Effects on Humans. Heliyon.
- 3
★Sweta Ghosh, Syam P. Nukavarpu, Venkatakrishna Rao Jala (2024). Effects of Heavy Metals on Gut Barrier Integrity and Gut Microbiota. Microbiota and Host.
- 4
★Robert J. Maier, Stéphane L. Benoit (2019). Role of Nickel in Microbial Pathogenesis. Inorganics.
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Created “Cysteine”: Cysteine is a sulfur-containing amino acid whose thiol (-SH) group makes it the primary metal-binding residue in biology. It is the rate-limiting precursor for glutathione (the master intracellular…
Created “Cysteine”: Cysteine is a sulfur-containing amino acid whose thiol (-SH) group makes it the primary metal-binding residue in biology. It is the rate-limiting precursor for glutathione (the master intracellular… Published sections: Overview; Metal Binding; Microbial Context; Cross-References. · WikiBiome Deploy Bot · +44 −0
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