Limits...
Uptake of L-cystine via an ABC transporter contributes defense of oxidative stress in the L-cystine export-dependent manner in Escherichia coli.

Ohtsu I, Kawano Y, Suzuki M, Morigasaki S, Saiki K, Yamazaki S, Nonaka G, Takagi H - PLoS ONE (2015)

Bottom Line: Another protein YecSC is the FliY-dependent L-cystine transporter that functions cooperatively with the L-cystine transporter YdeD, which exports L-cystine as reducing equivalents from the cytoplasm to the periplasm, to prevent E. coli cells from oxidative stress.The exported L-cystine can reduce the periplasmic hydrogen peroxide to water, and then generated L-cystine is imported back into the cytoplasm via the ATP-binding cassette transporter YecSC with a high affinity to L-cystine (Km = 110 nM) in a manner dependent on FliY, the periplasmic L-cystine-binding protein.From these findings, we propose that the hydrogen peroxide-inducible L-cystine/L-cystine shuttle system plays a role of detoxification of hydrogen peroxide before lipid peroxidation occurs, and then might specific prevent damage to membrane lipids.

View Article: PubMed Central - PubMed

Affiliation: Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara, Japan.

ABSTRACT
Intracellular thiols like L-cystine and L-cystine play a critical role in the regulation of cellular processes. Here we show that Escherichia coli has two L-cystine transporters, the symporter YdjN and the ATP-binding cassette importer FliY-YecSC. These proteins import L-cystine, an oxidized product of L-cystine from the periplasm to the cytoplasm. The symporter YdjN, which is expected to be a new member of the L-cystine regulon, is a low affinity L-cystine transporter (Km = 1.1 μM) that is mainly involved in L-cystine uptake from outside as a nutrient. E. coli has only two L-cystine importers because ΔydjNΔyecS mutant cells are not capable of growing in the minimal medium containing L-cystine as a sole sulfur source. Another protein YecSC is the FliY-dependent L-cystine transporter that functions cooperatively with the L-cystine transporter YdeD, which exports L-cystine as reducing equivalents from the cytoplasm to the periplasm, to prevent E. coli cells from oxidative stress. The exported L-cystine can reduce the periplasmic hydrogen peroxide to water, and then generated L-cystine is imported back into the cytoplasm via the ATP-binding cassette transporter YecSC with a high affinity to L-cystine (Km = 110 nM) in a manner dependent on FliY, the periplasmic L-cystine-binding protein. The double disruption of ydeD and fliY increased cellular levels of lipid peroxides. From these findings, we propose that the hydrogen peroxide-inducible L-cystine/L-cystine shuttle system plays a role of detoxification of hydrogen peroxide before lipid peroxidation occurs, and then might specific prevent damage to membrane lipids.

No MeSH data available.


Related in: MedlinePlus

Putative CySS importer genes in E. coli.(A) ABC type CySS importer gene operon and the encoded protein constitution on the cytoplasmic membrane in Lactobacillus reuteri and the homologous counterpart in E. coli. (B) Symporter type CySS importer gene and the encoded protein constitution on the cytoplasmic membrane in Bacillus subtilis and the homologous counterpart in E. coli. The identities in amino acid sequences of homologous genes are indicated. CySS, cystine.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4383340&req=5

pone.0120619.g001: Putative CySS importer genes in E. coli.(A) ABC type CySS importer gene operon and the encoded protein constitution on the cytoplasmic membrane in Lactobacillus reuteri and the homologous counterpart in E. coli. (B) Symporter type CySS importer gene and the encoded protein constitution on the cytoplasmic membrane in Bacillus subtilis and the homologous counterpart in E. coli. The identities in amino acid sequences of homologous genes are indicated. CySS, cystine.

Mentions: Some CySS importers known in bacteria are mainly classified into two types. One belongs to the ATP-binding cassette (ABC) transporter family. Lactobacillus reutei BR11 possesses the cyuABC operon, which is involved in the CySS-mediated oxidative defense (Fig. 1A) [11]. The inner membrane-spanning protein CyuA, the cytoplasmic ATP-binding protein CyuB, and the periplasmic CySS-binding protein CyuC form a complex on the cytoplasmic membrane. Bacillus subtilis also harbors three CySS importer systems that include two ABC transporters, TcyABC and TcyJKLMN, and another symporter TcyP [12]. In comparison to these known proteins, the FliY protein, which contributes to the CySS uptake in E. coli, exhibits sequence identities to CyuC, TcyA, TcyJ, and TcyK (30–40%, Fig. 1A). In E. coli, the fliY gene is unlikely to form an operon structure because probable terminator is located at its downstream. However, the putative dcyD-yecSC operon locates at the immediate downstream of fliY (Fig. 1A). The YecS and YecC proteins exhibit significant similarities in amino acid sequences to CyuA (49%) and CyuB (51%), respectively. YecC harbors the Walker A, Walker B, and ABC signature motifs required for ATPase activity, which is highly conservative to CyuB (S1 Fig.). These facts suggest that YecSC is a FliY-dependent CySS importer (FliY-YecSC) in E. coli. The E. coli dcyD (PLP-dependent d-cysteine desulfhydrase) gene is additionally present in the dcyD-yecSC operon and thus might work coincidentally with YecSC, although the counterpart gene is absent in CySS importer operon in L. reutei (Fig. 1A). The cystine, which is imported into the cytoplasm, might be immediately degraded to ammonium, pyruvate, and hydrogen sulfide by DcyD.


Uptake of L-cystine via an ABC transporter contributes defense of oxidative stress in the L-cystine export-dependent manner in Escherichia coli.

Ohtsu I, Kawano Y, Suzuki M, Morigasaki S, Saiki K, Yamazaki S, Nonaka G, Takagi H - PLoS ONE (2015)

Putative CySS importer genes in E. coli.(A) ABC type CySS importer gene operon and the encoded protein constitution on the cytoplasmic membrane in Lactobacillus reuteri and the homologous counterpart in E. coli. (B) Symporter type CySS importer gene and the encoded protein constitution on the cytoplasmic membrane in Bacillus subtilis and the homologous counterpart in E. coli. The identities in amino acid sequences of homologous genes are indicated. CySS, cystine.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4383340&req=5

pone.0120619.g001: Putative CySS importer genes in E. coli.(A) ABC type CySS importer gene operon and the encoded protein constitution on the cytoplasmic membrane in Lactobacillus reuteri and the homologous counterpart in E. coli. (B) Symporter type CySS importer gene and the encoded protein constitution on the cytoplasmic membrane in Bacillus subtilis and the homologous counterpart in E. coli. The identities in amino acid sequences of homologous genes are indicated. CySS, cystine.
Mentions: Some CySS importers known in bacteria are mainly classified into two types. One belongs to the ATP-binding cassette (ABC) transporter family. Lactobacillus reutei BR11 possesses the cyuABC operon, which is involved in the CySS-mediated oxidative defense (Fig. 1A) [11]. The inner membrane-spanning protein CyuA, the cytoplasmic ATP-binding protein CyuB, and the periplasmic CySS-binding protein CyuC form a complex on the cytoplasmic membrane. Bacillus subtilis also harbors three CySS importer systems that include two ABC transporters, TcyABC and TcyJKLMN, and another symporter TcyP [12]. In comparison to these known proteins, the FliY protein, which contributes to the CySS uptake in E. coli, exhibits sequence identities to CyuC, TcyA, TcyJ, and TcyK (30–40%, Fig. 1A). In E. coli, the fliY gene is unlikely to form an operon structure because probable terminator is located at its downstream. However, the putative dcyD-yecSC operon locates at the immediate downstream of fliY (Fig. 1A). The YecS and YecC proteins exhibit significant similarities in amino acid sequences to CyuA (49%) and CyuB (51%), respectively. YecC harbors the Walker A, Walker B, and ABC signature motifs required for ATPase activity, which is highly conservative to CyuB (S1 Fig.). These facts suggest that YecSC is a FliY-dependent CySS importer (FliY-YecSC) in E. coli. The E. coli dcyD (PLP-dependent d-cysteine desulfhydrase) gene is additionally present in the dcyD-yecSC operon and thus might work coincidentally with YecSC, although the counterpart gene is absent in CySS importer operon in L. reutei (Fig. 1A). The cystine, which is imported into the cytoplasm, might be immediately degraded to ammonium, pyruvate, and hydrogen sulfide by DcyD.

Bottom Line: Another protein YecSC is the FliY-dependent L-cystine transporter that functions cooperatively with the L-cystine transporter YdeD, which exports L-cystine as reducing equivalents from the cytoplasm to the periplasm, to prevent E. coli cells from oxidative stress.The exported L-cystine can reduce the periplasmic hydrogen peroxide to water, and then generated L-cystine is imported back into the cytoplasm via the ATP-binding cassette transporter YecSC with a high affinity to L-cystine (Km = 110 nM) in a manner dependent on FliY, the periplasmic L-cystine-binding protein.From these findings, we propose that the hydrogen peroxide-inducible L-cystine/L-cystine shuttle system plays a role of detoxification of hydrogen peroxide before lipid peroxidation occurs, and then might specific prevent damage to membrane lipids.

View Article: PubMed Central - PubMed

Affiliation: Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara, Japan.

ABSTRACT
Intracellular thiols like L-cystine and L-cystine play a critical role in the regulation of cellular processes. Here we show that Escherichia coli has two L-cystine transporters, the symporter YdjN and the ATP-binding cassette importer FliY-YecSC. These proteins import L-cystine, an oxidized product of L-cystine from the periplasm to the cytoplasm. The symporter YdjN, which is expected to be a new member of the L-cystine regulon, is a low affinity L-cystine transporter (Km = 1.1 μM) that is mainly involved in L-cystine uptake from outside as a nutrient. E. coli has only two L-cystine importers because ΔydjNΔyecS mutant cells are not capable of growing in the minimal medium containing L-cystine as a sole sulfur source. Another protein YecSC is the FliY-dependent L-cystine transporter that functions cooperatively with the L-cystine transporter YdeD, which exports L-cystine as reducing equivalents from the cytoplasm to the periplasm, to prevent E. coli cells from oxidative stress. The exported L-cystine can reduce the periplasmic hydrogen peroxide to water, and then generated L-cystine is imported back into the cytoplasm via the ATP-binding cassette transporter YecSC with a high affinity to L-cystine (Km = 110 nM) in a manner dependent on FliY, the periplasmic L-cystine-binding protein. The double disruption of ydeD and fliY increased cellular levels of lipid peroxides. From these findings, we propose that the hydrogen peroxide-inducible L-cystine/L-cystine shuttle system plays a role of detoxification of hydrogen peroxide before lipid peroxidation occurs, and then might specific prevent damage to membrane lipids.

No MeSH data available.


Related in: MedlinePlus