Lysine exporter
| D- and L-lysine, histidine and arginine exporter (LysE) | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Identifiers | |||||||||
| Symbol | LysE aka CGL1262 | ||||||||
| Pfam | PF01810 | ||||||||
| InterPro | IPR001123 | ||||||||
| |||||||||
The Lysine Exporter (LysE) Superfamily of integral membrane transport proteins was named based on the early discovery of the LysE carrier protein of Corynebacterium glutamicum (TC# 2.A.75.1.1), a Gram-positive bacterium, and its related counterparts. Families whose members of which exhibit similar sizes, hydropathy profiles, and sequence motifs comprise the LysE superfamily.[1] The LysE Superfamily was first described by Vrijic et al., (1999) and contained only 3 families, but it was greatly expanded to 11 families by Tsu and Saier (2015).[1][2] The LysE superfamily consists of transmembrane transport proteins that catalyze export of amino acids, lipids and heavy metal ions. Statistical means were used to show that it includes newly identified families including transporters specific for (1) tellurium, (2) iron/lead, (3) manganese, (4) calcium, (5) nickel/cobalt, (6) amino acids, and (7) peptidoglycolipids as well as (8) one family of transmembrane electron carriers. Internal repeats and conserved motifs were identified, and multiple alignments, phylogenetic trees and average hydropathy, amphipathicity and similarity plots provided evidence that all members of the superfamily derived from a single common 3-TMS precursor peptide via intragenic duplication. Their common origin implies that they share common structural, mechanistic and functional attributes. The transporters of this superfamily play important roles in ionic homeostasis, cell envelope assembly, and protection from excessive cytoplasmic heavy metal/metabolite concentrations. They thus influence the physiology and pathogenesis of numerous microbes, being potential targets of drug action.[2]
Families
2.A.75 - The L-Lysine Exporter (LysE) Family
2.A.76 - The Resistance to Homoserine/Threonine (RhtB) Family
2.A.77 - The Cadmium Resistance (CadD) Family
2.A.95 - The 6TMS Neutral Amino Acid Transporter (NAAT) Family
2.A.106 - The Ca2+:H+ Antiporter-2 (CaCA2) Family
2.A.107 - The Mn2+ exporter (MntP) Family
2.A.108 - The Iron/Lead Transporter (ILT) Family
2.A.109 - The Tellurium Ion Resistance (TerC) Family
2.A.113 - The Nickel/Cobalt Transporter (NicO) Family
2.A.116 - The Peptidoglycolipid Addressing Protein (GAP) Family
5.A.1 - The Disulfide Bond Oxidoreductase D (DsbD) Family
The LysE family
Two members of the LysE family (LysE of Corynebacterium glutamicum (TC# 2.A.75.1.1) and ArgO of E. coli) have been functionally characterized, but functionally uncharacterized homologues are encoded within the genomes of many bacteria including Bacillus subtilis, Mycobacterium tuberculosis, Aeromonas salmonicida, Helicobacter pylori, Vibrio cholerae and Yersinia pestis. Thus, LysE family members are found widely distributed in Gram-negative and Gram-positive bacteria.
Structure
These proteins are 190-240 amino acyl residues in length and possess six hydrophobic regions. PhoA fusion analyses of LysE of C. glutamicum provided evidence for a 5 transmembrane α-helical spanner (TMS) typology with the N-terminus inside and the C-terminus outside.[3] However, some evidence suggests a 6 TMS topology (R. Kramer, personal communication with Dr. Milton Saier, creator and administrator of TCDB).[4]
Function
LysE appears to catalyze unidirectional efflux of L-lysine (and other basic amino acids such as L-arginine), and it provides the sole route for L-lysine excretion. The energy source is believed to be the proton motive force (H+ antiport). The E. coli ArgO homologue (TC# 2.A.75.1.2) effluxes arginine and possibly lysine and canavanine as well.[5]
Early studies showed that the LysE family is related to the RhtB family (TC #2.A.76) as well as the CadD family (TC #2.A.77) based both on the similar sizes and topologies of their members and on PSI-BLAST results.[3]
Generalized Transport Reaction
The generalized transport reaction for LysE is:
Lysine (in) + [nH+ (out) or nOH- (in)] Lysine (out) + [nH+ (in) or nOH- (out)].
References
This article incorporates text available under the CC BY 4.0 license.
- 1 2 Vrljic, M.; Garg, J.; Bellmann, A.; Wachi, S.; Freudl, R.; Malecki, M. J.; Sahm, H.; Kozina, V. J.; Eggeling, L. (1999-11-01). "The LysE superfamily: topology of the lysine exporter LysE of Corynebacterium glutamicum, a paradyme for a novel superfamily of transmembrane solute translocators". Journal of Molecular Microbiology and Biotechnology 1 (2): 327–336. ISSN 1464-1801. PMID 10943564.
- 1 2 Tsu, Brian V.; Saier, Milton H. (2015-01-01). "The LysE Superfamily of Transport Proteins Involved in Cell Physiology and Pathogenesis". PloS One 10 (10): e0137184. doi:10.1371/journal.pone.0137184. ISSN 1932-6203. PMC 4608589. PMID 26474485.
- 1 2 Vrljic, M.; Sahm, H.; Eggeling, L. (1996-12-01). "A new type of transporter with a new type of cellular function: L-lysine export from Corynebacterium glutamicum". Molecular Microbiology 22 (5): 815–826. ISSN 0950-382X. PMID 8971704.
- ↑ Saier, MH Jr. "2.A.75 The L-Lysine Exporter (LysE) Family". Transporter Classification Database. Saier Lab Bioinformatics Group / SDSC.
- ↑ Nandineni, Madhusudan R.; Gowrishankar, J. (2004-06-01). "Evidence for an arginine exporter encoded by yggA (argO) that is regulated by the LysR-type transcriptional regulator ArgP in Escherichia coli". Journal of Bacteriology 186 (11): 3539–3546. doi:10.1128/JB.186.11.3539-3546.2004. ISSN 0021-9193. PMC 415761. PMID 15150242.