Scholarlink

Background <p>We dissolved in 8 M urea solution molecularly characterized humeomes isolated from either soils or geochemical sources to follow their conformational behavior when eluted in a high-performance size-exclusion chromatography (HPSEC) system and detected by both UV and Refractive Index (RI) detectors.</p> Results <p>The UV-detected chromatographic profile showed only an intense absorbance at the column void volume, where the RI detector instead revealed just a small peak. Concomitantly, the large humeomes mass was RI-detected as a large absorption uniquely at the column total volume. This peculiar behavior was explained with the highly structured urea-water network exerting a strong hydrophobic effect that forced the apolar humic molecules into apparently large clusters eluting at the void volume of the HPSEC column, while polar and medium polar components were separated from each other by the strong hydrogen bonding capacity of the urea solution and diffused through the column micropores up to the total volume. The intensity difference between UV and RI detections indicates that the UV-detected hydrophobic assemblies contained only few aromatic groups, but their enforced proximity favored mutual charge-transfer interactions, thus providing a hyperchromic effect with absorbances larger than the sum of single aromatic chromophores. Three different soils incubated for one year with maize residues provided HPSEC profiles which suggested altered humic composition. Changes in aromatic groups, as revealed by 13C-NMR spectra, affected the intensity of UV-detected peaks of hydrophobic clusters, while different amounts of polar and medium-polar molecules determined the humeomes conformational rigidity, varying the RI signals at the column total volume.</p> Conclusions <p>Our results indicated that a concentrated urea solution was capable to unfold the weakly-bound humic associations and efficiently separating components of different chemical affinity, thereby confirming the supramolecular structure of humeomes, and representing a useful technique to simplify their heterogeneity, facilitate their molecular characterization, and understand their role in the agroecosystem.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Unfolding the conformational structure of supramolecular humeomes in 8 M urea

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2026年6月15日

查看全文
  • Alessandro Piccolo,
  • Marios Drosos,
  • Giovanni Vinci

摘要

Background

We dissolved in 8 M urea solution molecularly characterized humeomes isolated from either soils or geochemical sources to follow their conformational behavior when eluted in a high-performance size-exclusion chromatography (HPSEC) system and detected by both UV and Refractive Index (RI) detectors.

Results

The UV-detected chromatographic profile showed only an intense absorbance at the column void volume, where the RI detector instead revealed just a small peak. Concomitantly, the large humeomes mass was RI-detected as a large absorption uniquely at the column total volume. This peculiar behavior was explained with the highly structured urea-water network exerting a strong hydrophobic effect that forced the apolar humic molecules into apparently large clusters eluting at the void volume of the HPSEC column, while polar and medium polar components were separated from each other by the strong hydrogen bonding capacity of the urea solution and diffused through the column micropores up to the total volume. The intensity difference between UV and RI detections indicates that the UV-detected hydrophobic assemblies contained only few aromatic groups, but their enforced proximity favored mutual charge-transfer interactions, thus providing a hyperchromic effect with absorbances larger than the sum of single aromatic chromophores. Three different soils incubated for one year with maize residues provided HPSEC profiles which suggested altered humic composition. Changes in aromatic groups, as revealed by 13C-NMR spectra, affected the intensity of UV-detected peaks of hydrophobic clusters, while different amounts of polar and medium-polar molecules determined the humeomes conformational rigidity, varying the RI signals at the column total volume.

Conclusions

Our results indicated that a concentrated urea solution was capable to unfold the weakly-bound humic associations and efficiently separating components of different chemical affinity, thereby confirming the supramolecular structure of humeomes, and representing a useful technique to simplify their heterogeneity, facilitate their molecular characterization, and understand their role in the agroecosystem.