투고논문

High-pressure NMR analysis on Escherichia coli IscU

Jongbum Na,^# Jinbeom Si,^# and Jin Hae Kim*

Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology, Daegu 42988, Republic of Korea

Received Mar 18, 2024; Revised Mar 19, 2024; Accepted Mar 19, 2024

 Abstract IscU, the iron-sulfur (Fe-S) cluster scaffold protein, is an essential protein for biogenesis of Fe-S clusters. Previous studies showed that IscU manifests a metamorphic structural feature; at least two structural states, namely the structured state (S-state) and the disordered state (D-state), interconverting in a physiological condition, was observed. Moreover, subsequent studies demonstrated that the metamorphic flexibility of IscU is important for its Fe-S cluster assembly activity as well as for an efficient interaction with various partner proteins. Although solution nuclear magnetic resonance (NMR) spectroscopy has been a useful tool to investigate this protein, the detailed molecular mechanism that sustains the structural heterogeneity of IscU is still unclear. To tackle this issue, we applied a high-pressure NMR (HP-NMR) technique to the IscU variant, IscU(I8K), which shows an increased population of the S-state. We found that the equilibrium between the S- and D-state was significantly perturbed by pressure application, and the specific regions of IscU exhibited more sensitivity to pressure than the other regions. Our results provide novel insights to appreciate the dynamic behaviors of IscU and the related versatile functionality.

Keywords IscU, iron-sulfur cluster biogenesis, NMR spectroscopy, high-pressure NMR, metamorphic protein

 ^# These authors contributed equally.

* Address correspondence to: Jin Hae Kim, Department of New Biology, Daegu Gyeongbuk Institute of Science &Technology, Daegu 42988, Republic of Korea, Tel: 82-53-785-1770; E-mail: jinhaekim@dgist.ac.kr