title: [Conservative motif CMLD in silicic acid transport proteins of diatom algae].
abstract: Sequencing of fragments of genes coding for silicic acid transport (SIT) proteins of diatoms of evolutionary distant classes (centric Chaetoceros muelleri Lemmermann, pennate araphid Synedra acus Kützing, pennate raphid Phaeodactylum tricornutum Bohlin, and pennate with keeled raphe system Cylindrotheca fusiformis Reimann et Lewin), revealed the presence in these proteins of a conservative amino acid motif CMLD. Hydropathy profiles suggest that CMLD occupies a position between two transmembrane strands which do not contain lysine and arginine residues. The two strands are good candidates for the role of the channel along which transport of silicic acid occurs. CMLD is a rare motif. Diatoms are known to need Zn2+ for the incorporation of silica. Presumably, CMLD is the site of Zn2+ binding of SITs. We found that the growth of diatoms is inhibited by a negatively charged alkylating reagent 5-(2-iodoacetamidoethyl)aminonaphtalene-1-sulfonic acid which cannot penetrate through the cell membrane. Cysteine of CMLD can be a target of this reagent. Synthetic peptide NCMLDY forms a complex with Zn2+, as revealed by the fact that the ion considerably reduces the rate of alkylation of the peptide.
authors.forename: T A
authors.initials: TA
authors.lastname: Shcherbakova
authors.forename: Iu A
authors.initials: IuA
authors.lastname: Masiukova
authors.forename: T A
authors.initials: TA
authors.lastname: Safonova
authors.forename: D P
authors.initials: DP
authors.lastname: Petrova
authors.forename: A L
authors.initials: AL
authors.lastname: Vereshchagin
authors.forename: T V
authors.initials: TV
authors.lastname: Minaeva
authors.forename: R V
authors.initials: RV
authors.lastname: Adel'shin
authors.forename: T I
authors.initials: TI
authors.lastname: Triboĭ
authors.forename: I V
authors.initials: IV
authors.lastname: Stonik
authors.forename: N A
authors.initials: NA
authors.lastname: Aĭzdaĭcher
authors.forename: M V
authors.initials: MV
authors.lastname: Kozlov
authors.forename: E V
authors.initials: EV
authors.lastname: Likhoshvaĭ
authors.forename: M A
authors.initials: MA
authors.lastname: Grachev
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001483:Base Sequence; D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004247:DNA; D017377:Diatoms / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D012824:Silicic Acid / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D012824:Silicic Acid; D004247:DNA