40 KB685 KB28 KB199820252011Novič, MarjanaPassamonti, SabinaRoy Choudhury, AmritaŽuperl, Špelaštevilka:3letnik:58str. 385-392ISSN:1318-0207COBISSID:4798234URN:URN:NBN:SI:doc-PEHWTJCQenSlovenian Chemical SocietySlovensko kemijsko društvoActa chimica slovenicapodatkovne zbirkeproteinistrukturna kemijaStructure elucidation of transmembrane proteins using public-available databases and experimental data on competitive inhibition|We present an approach towards structure elucidation of bilitranslocase, the membrane protein which transports bilirubin from blood to liver cells. The sequence and secondary structure information of transmembrane segments of proteins with known 3D structure is exploited to predict the transmembrane domains of structurally unresolved target protein. With the help of known structures the transmembrane domains are encoded in such a way that it is possible to group and classify them with respect to their specific sub-structural characteristics and to build a model for prediction of transmembrane segments. We have shown that the model for prediction of transmembrane segments proposed four transmembrane alpha helices, each containing around 20 amino acids. This result is partially confirmed with experimental studies using particular antibodies corresponding to parts of amino acid sequences of bilitranslocase. In order to shed light on the bilitranslocase transport mechanism, we also tested a set of non-congeneric compounds for their competitive inhibition constants in the investigated protein-substrate system. The information about chemical structure of small molecules that either pass or block the transmembrane path enabled by bilitranslocase helps us to build a hypothesis about the transport mechanism of the studied biological systemPredstavljen je pristop k analizi kemijske strukture bilitranslokaze, membranskega proteina, ki prenaša bilirubin iz krvi v jetrne celice. Zaporedje aminokislin in informacije o sekundarni strukturi transmembranskih segmentov proteinov s poznano 3D strukturo uporabimo za napovedovanje transmembranskih domen strukturno nerešenih proteinov. S pomočjo poznanih struktur kodiramo transmembranske in ostale domene proteinov na tak način, da jih lahko s pomočjo računalniških programov grupiramo glede na njihove podstrukturne karakteristike in da lahko zgradimo model za napovedovanje transmembranskih segmentov. Prikazan model za napovedovanje transmembranski segmentov identificira štiri transmembranske alfa vijačnice, od katerih vsaka vsebuje okoli 20 aminokislin. Ta rezultat je delno potrjen z eksperimentalnimi študijami uporabe določenih protiteles, ki ustrezajo delom aminokislinskega zaporedja bilitranslokaze. Da bi razjasnili transportni mehanizem bilitranslokaze, smo testirali tudi niz strukturno raznolikih spojin za določitev njihove kompetitivne konstante inhibicije v preiskovanem sistemu protein-substrat. Informacija o kemijski strukturi majhnih molekul, ki ali prehajajo ali blokirajo transmembransko pot preko bilitranslokaze, nam pomaga graditi hipotezo o transportnem mehanizmu študiranega biološkega sistemaTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaSlovensko kemijsko društvo