Insights into the Structure of the Chloroplast Phosphate Translocator Protein

Wallmeier, Holger; Weber, Andreas; Gross, Armin; Flügge, Ulf‐Ingo

doi:10.1007/978-1-4615-3442-6_7

Cited by 6 publications

(3 citation statements)

References 15 publications

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“…Early transport kineticists concluded that its demonstration eliminated the possibility that a transporter functions by a channel-type mechanism and suggested that clear boundaries exist between carriers and channels (79,135). Subsequent observations that certain "carriers" could apparently be converted into "channels" by chemical treatment (16,17,28,29,56), by imposition of large membrane potentials (131,132,149), or by ligand binding (13) led many students of transport to consider these boundaries indistinct. Our in silico phylogenetic and protein structural analyses suggest that these examples may be special cases and tend to reemphasize the importance of the channel-versus-carrier distinction (123,127).…”

Section: Transport Nomenclaturementioning

confidence: 99%

“…Such promiscuous use of energy is exceptionally rare and has been documented in only (16,17,28,29,56), or imposition of a large membrane potential (⌬⌿) across a membrane into which a TP-NST family member has been incorporated (131,132,149), has been reported to convert these antiport-catalyzing carriers into anion-selective channels capable of functioning by uniport. Another secondary carrier that may be capable of exhibiting channel-like properties is the KefC protein of E. coli (13), which is a member of the CPA2 family (TC 2.A.37).…”

Section: Families Of Transportersmentioning

confidence: 99%

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A Functional-Phylogenetic Classification System for Transmembrane Solute Transporters

Saier

2000

Microbiol Mol Biol Rev

748

642

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SUMMARY A comprehensive classification system for transmembrane molecular transporters has been developed and recently approved by the transport panel of the nomenclature committee of the International Union of Biochemistry and Molecular Biology. This system is based on (i) transporter class and subclass (mode of transport and energy coupling mechanism), (ii) protein phylogenetic family and subfamily, and (iii) substrate specificity. Almost all of the more than 250 identified families of transporters include members that function exclusively in transport. Channels (115 families), secondary active transporters (uniporters, symporters, and antiporters) (78 families), primary active transporters (23 families), group translocators (6 families), and transport proteins of ill-defined function or of unknown mechanism (51 families) constitute distinct categories. Transport mode and energy coupling prove to be relatively immutable characteristics and therefore provide primary bases for classification. Phylogenetic grouping reflects structure, function, mechanism, and often substrate specificity and therefore provides a reliable secondary basis for classification. Substrate specificity and polarity of transport prove to be more readily altered during evolutionary history and therefore provide a tertiary basis for classification. With very few exceptions, a phylogenetic family of transporters includes members that function by a single transport mode and energy coupling mechanism, although a variety of substrates may be transported, sometimes with either inwardly or outwardly directed polarity. In this review, I provide cross-referencing of well-characterized constituent transporters according to (i) transport mode, (ii) energy coupling mechanism, (iii) phylogenetic grouping, and (iv) substrates transported. The structural features and distribution of recognized family members throughout the living world are also evaluated. The tabulations should facilitate familial and functional assignments of newly sequenced transport proteins that will result from future genome sequencing projects.

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Section: Transport Nomenclaturementioning

confidence: 99%

Section: Families Of Transportersmentioning

confidence: 99%

A Functional-Phylogenetic Classification System for Transmembrane Solute Transporters

Saier

2000

Microbiol Mol Biol Rev

748

642

View full text Add to dashboard Cite

show abstract

“…Based on a tentative model for the arrangement of the TPT in the membrane, it is probable that all 12 α-helices of the phosphate translocator dimer take part in forming a hydrophilic translocation channel through which the substrates could be transported across the membrane (75). Interestingly, two successive charged residues in helix V (Lysine, Arginine) that have been proposed to be involved in substrate binding (10) are conserved in all phosphate transport proteins.…”

Section: Molecular Identification and Characterization Of Plastidic Pmentioning

confidence: 99%

Phosphate Translocators in Plastids

Flügge

1999

Annu. Rev. Plant. Physiol. Plant. Mol. Biol.

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206

153

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During photosynthesis, energy from solar radiation is used to convert atmospheric carbon dioxide into intermediates that are used within and outside the chloroplast for a multitude of metabolic pathways. The daily fixed carbon is exported from the chloroplasts as triose phosphates and 3-phosphoglycerate. In contrast, nongreen plastids rely on the import of carbon, mainly hexose phosphates. Most organelles require the import of phosphoenolpyruvate as an immediate substrate for carbon to enter the shikimate pathway, leading to a variety of important secondary compounds. The envelope membrane of plastids contains specific translocators that are involved in these transport processes. Elucidation of the molecular structure of some of these translocators during the past few years has provided new insights in the functioning of particular translocators. This review focuses on the characterization of different classes of phosphate translocators in plastids that mediate the transport of the phosphorylated compounds in exchange with inorganic phosphate.

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Metabolite Transport Across the Chloroplast Envelope of C3-Plants

Flügge

2000

Photosynthesis

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Insights into the Structure of the Chloroplast Phosphate Translocator Protein

Cited by 6 publications

References 15 publications

A Functional-Phylogenetic Classification System for Transmembrane Solute Transporters

A Functional-Phylogenetic Classification System for Transmembrane Solute Transporters

Phosphate Translocators in Plastids

Metabolite Transport Across the Chloroplast Envelope of C3-Plants

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