Crystallographic analysis of Eisenia hydrolysis-enhancing protein using a long wavelength for native-SAD phasing

Xiaomei Sun, Yuxin Ye, Naofumi Sakurai, Koji Kato, Keizo Yuasa, Akihiko Tsuji, Min Yao

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


Eisenia hydrolysis-enhancing protein (EHEP), which is a novel protein that has been identified in Aplysia kurodai, protects β-glucosidases from phlorotannin inhibition to facilitate the production of glucose from the laminarin abundant in brown algae. Hence, EHEP has attracted attention for its potential applications in producing biofuel from brown algae. In this study, EHEP was purified from the natural digestive fluid of A. kurodai and was crystallized using the sitting-drop vapor-diffusion method. Native and SAD (single-wavelength anomalous diffraction) data sets were successfully collected at resolutions of 1.20 and 2.48Å using wavelengths of 1.0 and 2.1Å, respectively, from crystals obtained in initial screening. The crystals belonged to space group P212121 and contained one EHEP molecule in the asymmetric unit. All 20 S-atom sites in EHEP were located and the phases were determined by the SAD method using the S atoms in the natural protein as anomalous scatterers (native-SAD). After phase improvement, interpretable electron densities were obtained and 58% of the model was automatically built.

Original languageEnglish
Pages (from-to)20-24
Number of pages5
JournalActa Crystallographica Section F: Structural Biology Communications
Publication statusPublished - Jan 1 2020
Externally publishedYes


  • EHEP
  • biofuel
  • native-SAD
  • phlorotannin binding
  • solutionless crystal mount

ASJC Scopus subject areas

  • Biophysics
  • Structural Biology
  • Biochemistry
  • Genetics
  • Condensed Matter Physics


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