title: Study of the specific interaction between L-methionine chromatography support and nucleotides.
abstract: The interaction of L-methionine-agarose with 5'-mononucleotide was investigated by saturation transfer difference (STD)-nuclear magnetic resonance (NMR) spectroscopy. Chromatographic experiments were also performed using homo-oligonucleotides of distinct molecular masses (1-30 nucleotides) to explore the effect of base hydrophobicity, temperature, pH and salt concentration on the retention of homo-oligonucleotides to L-methionine-agarose support. With STD-NMR, the results reveal that hydrophobic residues, such as the CH₃ of thymine and adenine, can preferentially recognise the L-methionine side chain of the support. Also, 5'-TMP led to more contacts with the support, while 5'-UMP presented fewer STD contacts. For 5'-UMP, 5'-CMP and 5'-GMP, the main interaction with the support was through the sugar-phosphate backbone. Similar binding profiles were obtained using chromatographic experiments. Indeed, 5'-TMP had the highest retention time, followed by 5'-GMP, 3'-AMP, 5'-UMP and 5'-CMP. In general, the retention factor of homo-oligonucleotides was higher for ammonium sulphate concentration 1.5 M. For the polyT₃-polyT₃₀ series, the retention time increased by about three-fold, indicating that larger homo-oligonucleotides have more hydrophobic bases, thus enhancing contact with the L-methionine support. The temperature (5, 20 and 35 °C) did not influence homo-oligonucleotide retention. However, the retention time slightly increased when the pH was lower than 9. The STD-NMR technique combined with chromatographic experiments was thus successfully used to screen amino acid-nucleotide interactions.
authors.affiliation: CICS-UBI-Centro de Investigação em Ciências da Saúde, Universidade da Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal. carlacruz@fcsaude.ubi.pt
authors.forename: C
authors.initials: C
authors.lastname: Cruz
authors.forename: A
authors.initials: A
authors.lastname: Sousa
authors.forename: F
authors.initials: F
authors.lastname: Sousa
authors.forename: J A
authors.initials: JA
authors.lastname: Queiroz
mesh_terms: D002853:Chromatography, Liquid / Q000295:instrumentation / Q000379:methods*; D057927:Hydrophobic and Hydrophilic Interactions; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008715:Methionine / Q000737:chemistry*; D008958:Models, Molecular; D008970:Molecular Weight; D009994:Osmolar Concentration; D011119:Polynucleotides / Q000737:chemistry*; D012685:Sepharose
chemical_list: D011119:Polynucleotides; D012685:Sepharose; D008715:Methionine