A Charge Pair Interaction Between Arg282 in Transmembrane Segment 7  and Asp341 in Transmembrane Segment 8 of hPepT1

Kulkarni, Ashutosh A.; Davies, Daryl L.; Links, Jennifer S.; Patel, Leena N.; Lee, Vincent H.L.; Haworth, Ian S.

doi:10.1007/s11095-006-9119-x

Cited by 22 publications

(28 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…19,20 On the other hand, there is evidence from bioinformatics for ionic interactions in multispan membrane proteins, as these contain pairs of basic and acidic residues much more frequently than expected from random sampling. 21 In addition, a few cases in which ionic interactions between TMDs contribute to subunit assembly, as in the T-cell receptor complex, 22 a dipeptide transporter, 23 and voltage-activated ion channels, 24,25 are known. Charge-charge interactions between TMDs were also proposed to affect the location of helix pairs within the membrane.…”

Section: Introductionmentioning

confidence: 99%

Ionic Interactions Promote Transmembrane Helix–Helix Association Depending on Sequence Context

Herrmann

Fuchs

Panitz

et al. 2010

Journal of Molecular Biology

View full text Add to dashboard Cite

Section: Introductionmentioning

confidence: 99%

Ionic Interactions Promote Transmembrane Helix–Helix Association Depending on Sequence Context

Herrmann

Fuchs

Panitz

et al. 2010

Journal of Molecular Biology

View full text Add to dashboard Cite

“…Previous results [17][18][19] have suggested that residues R282 and D341 form an ion bridge whose cyclic breaking and formation may gate the translocation process. Furthermore, it has been proposed [31] that PepT1 may represent a transitional entity between transporters and channels.…”

Section: Ion and Substrate Specificitymentioning

confidence: 92%

“…By using the cysteine scanning method, Kulkarni and coworkers [16] identified several residues important for the transport function in transmembrane segments 5 and 7 and suggested that these segments line the putative aqueous channel. Finally, the same authors identified two oppositely charged residues (R282 and D341) in transmembrane segments 7 and 8, respectively, that form a salt bridge and play an important role in the substrate translocation via PepT1 [17].…”

Section: Introductionmentioning

confidence: 92%

“…Of the two residues forming a putative charge pair in the PepT1 structure (R282 and D341), [17,18], only mutants in arginine 282 present the outward current phenotype (Fig. 1).…”

Section: Other Substratesmentioning

confidence: 99%

“…Arginine 282 is located in the seventh transmembrane segment of the protein, and it is believed to form a charge pair with another, negatively charged residue (aspartate 341), positioned at about the same level in transmembrane segment 8 (see inset in Fig. 1) [9,17,18]. Voltage pulses from -140 to ?40 mV were applied from V h = -60 mV.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Functional and structural determinants of reverse operation in the pH-dependent oligopeptide transporter PepT1

Renna

Oyadeyi

Bossi

et al. 2010

Cell. Mol. Life Sci.

View full text Add to dashboard Cite

The functional and structural basis of reverse operation of PepT1 has been studied in Xenopus oocytes expressing the wild-type and mutated forms of this protein. Using brief pulses from a negative holding potential, wild-type and Arg282 mutants exhibit outward currents in the presence of Gly-Gln. The reversal potential of these currents is affected by both pH and substrate concentration, confirming coupled transport in the wild type and in the mutants as well. Long-lasting voltage and current-clamp experiments show that the outward currents are only temporary, and reflect accumulation and/or depletion effects near the membrane. The ability to operate in reverse mode was confirmed in all isoforms by intracellular injection of substrate. The role of Arg282 and Asp341 in the reverse transport was also investigated using charged substrates. Positive Lys-Gly (but not Gly-Lys) showed enhanced transport currents in the Arg282 mutants. In contrast, negative Gly-Asp and Asp-Gly elicited modest currents in all isoforms.

show abstract

Transporters that translocate nucleosides and structural similar drugs: structural requirements for substrate recognition

Cano-Soldado

Pastor‐Anglada

2011

Medicinal Research Reviews

View full text Add to dashboard Cite

Nucleoside transporters (NT) are integral membrane proteins implicated in the salvage of natural nucleobases and nucleosides for nucleic acid synthesis. These proteins also play a crucial role as carriers of nucleoside analogs used in anticancer and antiviral therapies. In fact, differential expression patterns of NT subtypes among tissues and individuals as well as the existence of genetic variants affect nucleoside-derived drug permeation, and consequently, their pharmacokinetic and cytotoxic properties. Thus, NT expression patterns may be effective predictive markers of therapeutic response. While the structures of NT proteins are yet to be solved, specific residues responsible for interaction with substrates and inhibitors have been identified, providing further insights into their structure-function relationship. In addition to transporter structural features, several experimental approaches have been used to identify the structural requirements of nucleosides for interaction with Concentrative Nucleoside Transporters and Equilibrative Nucleoside Transporters (SLC28 and SLC29 gene families, respectively). Pharmacophore models proposed for both protein families may prove suitable for optimizing drug design. Additional transporter proteins, including Organic Anion Transporters, Organic Cation Transporters (members of the SLC22 gene family), and Peptide Transporters (SLC15 gene family), have been implicated in the uptake of nucleoside-derived drugs, particularly those currently used in antiviral therapies. In this review, we focus on the pharmacological profiles of these transporter proteins, summarizing the documented studies covering structure-function and substrate structural requirement properties that determine drug-carrier interaction and efficient substrate translocation across the plasma membrane of target cells.

show abstract

A Charge Pair Interaction Between Arg282 in Transmembrane Segment 7 and Asp341 in Transmembrane Segment 8 of hPepT1

Abstract: Our results are consistent with a salt bridge between R282 and D341 in hPepT1, and we use these and other data to propose a role for the R282-D341 charge pair in the hPepT1 translocation mechanism.

Cited by 22 publications

References 39 publications

Ionic Interactions Promote Transmembrane Helix–Helix Association Depending on Sequence Context

Ionic Interactions Promote Transmembrane Helix–Helix Association Depending on Sequence Context

Functional and structural determinants of reverse operation in the pH-dependent oligopeptide transporter PepT1

Transporters that translocate nucleosides and structural similar drugs: structural requirements for substrate recognition

Contact Info

Product

Resources

About