The Structure of G1pF, A Glycerol Conducting Channel

Fu, Dax; Libson, Andrew M.; Stroud, Robert M.

doi:10.1002/0470868759.ch5

Cited by 18 publications

(12 citation statements)

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“…mutans . glpF codes for a putative glycerol uptake facilitator protein [ 38 ]. It functions as a membrane channel that selectively transports water, small neutral molecules and ions out of and between cells.…”

Section: Resultsmentioning

confidence: 99%

Identification and Functional Analysis of Genome Mutations in a Fluoride-Resistant Streptococcus mutans Strain

et al. 2015

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It is known that fluoride-resistant microorganisms are different from fluoride-sensitive ones in growth, adherence and metabolic activity. It was hypothesized that these phenotypic differences were due to stable genotypic changes in the fluoride-resistant strains. However, until now, no studies have reported these genotypic changes. The aim of this study is to identify such changes in a fluoride-resistant Streptococcus mutans strain (C180-2FR) using whole-genome shotgun (WGS) sequencing and to examine the potential function of the identified mutations by comparing gene expression between the fluoride-sensitive (C180-2) and C180-2FR strains. We performed 50 bp paired-end Illumina shotgun sequencing for both strains. Through extensive bioinformatic analysis, we were able to identify 8 single nucleotide polymorphisms (SNPs) in the genome of C180-2FR, which were further confirmed by Sanger sequencing. Expression of the genes containing or in proximity to the SNPs in C180-2 and C180-2FR was then quantified by real-time PCR. A gene cluster containing genes coding for fluoride antiporters was up-regulated 10-fold in C180-2FR when compared to that in C180-2, independent of growth phase. Two SNPs are located in this gene cluster, one in its promoter region and the other in its protein-coding region. In addition, one gene, which codes for a putative glycerol uptake facilitator protein, was found to be down-regulated by 60% in C180-2FR at an early growth phase. The promoter region of this gene contained a SNP. No difference in expression was found for the other SNP-containing genes. In summary, using WGS sequencing, we were able to uncover genetic changes in the genome of a fluoride-resistant strain. These findings can provide new insights into the mechanism of microbial fluoride resistance.

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Section: Resultsmentioning

confidence: 99%

Identification and Functional Analysis of Genome Mutations in a Fluoride-Resistant Streptococcus mutans Strain

et al. 2015

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“…At every step in the process, information is obtained to improve the purity, stability and homogeneity of the subsequent preparations of the target protein, as well as to guide optimization of crystal growth conditions. The general protocol presented here has been used successfully by our group for the crystallization of several membrane proteins 32–38 . To make the process of generating such a protocol more transparent, some sections are accompanied by additional text in the Experimental design that highlights key parameters that require optimization.…”

Section: Experimental Designmentioning

confidence: 99%

“…Every membrane protein crystallized in our laboratory has been subject to SEC during purification 32–38 (Table 1). SEC is also a powerful tool in assessing the homogeneity, stability and purity of a protein target.…”

Section: Experimental Designmentioning

confidence: 99%

A general protocol for the crystallization of membrane proteins for X-ray structural investigation

et al. 2009

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Protein crystallography is used to generate atomic resolution structures of protein molecules. These structures provide information about biological function, mechanism and interaction of a protein with substrates or effectors including DNA, RNA, cofactors or other small molecules, ions and other proteins. This technique can be applied to membrane proteins resident in the membranes of cells. To accomplish this, membrane proteins first need to be either heterologously expressed or purified from a native source. The protein has to be extracted from the lipid membrane with a mild detergent and purified to a stable, homogeneous population that may then be crystallized. Protein crystals are then used for X-ray diffraction to yield atomic resolution structures of the desired membrane protein target. Below, we present a general protocol for the growth of diffraction quality membrane protein crystals. The process of protein crystallization is highly variable, and obtaining diffraction quality crystals can require weeks to months or even years in some cases.

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“…It appears that the ar/R constriction only permits the passage of dipoles that can interact with positive and negative charges simultaneously. Both cations and anions are excluded because neither can fulfill a dual role of polarization (Fu et al 2002). It is evident that both water and glycerol can satisfy the polarity and geometry requirements of the ar/R constrictions.…”

Section: Ar/r Constriction and Water/glycerol Selectivitymentioning

confidence: 99%

The structural basis of water permeation and proton exclusion in aquaporins (Review)

2007

Molecular Membrane Biology

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Aquaporins (AQPs) represent a ubiquitous class of integral membrane proteins that play critical roles in cellular osmoregulations in microbes, plants and mammals. AQPs primarily function as water-conducting channels, whereas members of a sub-class of AQPs, termed aquaglyceroporins, are permeable to small neutral solutes such as glycerol. While AQPs facilitate transmembrane permeation of water and/or small neutral solutes, they preclude the conduction of protons. Consequently, openings of AQP channels allow rapid water diffusion down an osmotic gradient without dissipating electrochemical potentials. Molecular structures of AQPs portray unique features that define the two central functions of AQP channels: effective water permeation and strict proton exclusion. This review describes AQP structures known to date and discusses the mechanisms underlying water permeation, proton exclusion and water permeability regulation.

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The Structure of G1pF, A Glycerol Conducting Channel

Cited by 18 publications

References 0 publications

Identification and Functional Analysis of Genome Mutations in a Fluoride-Resistant Streptococcus mutans Strain

Identification and Functional Analysis of Genome Mutations in a Fluoride-Resistant Streptococcus mutans Strain

A general protocol for the crystallization of membrane proteins for X-ray structural investigation

The structural basis of water permeation and proton exclusion in aquaporins (Review)

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