In this review we summarize the progress made towards understanding the role of protein-protein interactions in the function of various bioluminescence systems of marine organisms, including bacteria, jellyfish and soft corals, with particular focus on methodology used to detect and characterize these interactions. In some bioluminescence systems, protein-protein interactions involve an "accessory protein" whereby a stored substrate is efficiently delivered to the bioluminescent enzyme luciferase. Other types of complexation mediate energy transfer to an "antenna protein" altering the color and quantum yield of a bioluminescence reaction. Spatial structures of the complexes reveal an important role of electrostatic forces in governing the corresponding weak interactions and define the nature of the interaction surfaces. The most reliable structural model is available for the protein-protein complex of the Ca(2+)-regulated photoprotein clytin and green-fluorescent protein (GFP) from the jellyfish Clytia gregaria, solved by means of Xray crystallography, NMR mapping and molecular docking. This provides an example of the potential strategies in studying the transient complexes involved in bioluminescence. It is emphasized that structural studies such as these can provide valuable insight into the detailed mechanism of bioluminescence.
Animals ; Anthozoa ; physiology ; Aquatic Organisms ; physiology ; Bacteria ; metabolism ; Binding Sites ; Calcium ; metabolism ; Crystallography, X-Ray ; Fluorescence Resonance Energy Transfer ; Green Fluorescent Proteins ; metabolism ; Hydrozoa ; physiology ; Imidazoles ; metabolism ; Luciferases ; metabolism ; Luminescent Measurements ; instrumentation ; methods ; Luminescent Proteins ; metabolism ; Models, Molecular ; Protein Binding ; Pteridines ; metabolism ; Pyrazines ; metabolism ; Scyphozoa ; physiology ; Spectrometry, Fluorescence

Holo glutaredoxin (Grx) is a homo-dimer that bridges a [2Fe-2S] cluster with two glutathione (GSH) ligands. In this study, both monothiol and dithiol holo Grxs are found capable of transferring their iron-sulfur (FeS) cluster to an apo ferredoxin (Fdx) through direct interaction, regardless of FeS cluster stability in holo Grxs. The ligand GSH molecules in holo Grxs are unstable and can be exchanged with free GSH, which inhibits the FeS cluster transfer from holo Grxs to apo Fdx. This phenomenon suggests a novel role of GSH in FeS cluster trafficking.
Circular Dichroism ; Dimerization ; Ferredoxins ; chemistry ; metabolism ; Glutaredoxins ; chemistry ; metabolism ; Glutathione ; metabolism ; Iron ; chemistry ; Ligands ; Magnetic Resonance Spectroscopy ; Sulfhydryl Compounds ; chemistry ; Sulfur ; chemistry ; Toluene ; analogs & derivatives ; chemistry

Uch37 is a de-ubiquitinating enzyme that is activated by Rpn13 and involved in the proteasomal degradation of proteins. The full-length Uch37 was shown to exhibit low iso-peptidase activity and is thought to be auto-inhibited. Structural comparisons revealed that within a homo-dimer of Uch37, each of the catalytic domains was blocking the other's ubiquitin (Ub)-binding site. This blockage likely prevented Ub from entering the active site of Uch37 and might form the basis of auto-inhibition. To understand the mode of auto-inhibition clearly and shed light on the activation mechanism of Uch37 by Rpn13, we investigated the Uch37-Rpn13 complex using a combination of mutagenesis, biochemical, NMR, and small-angle X-ray scattering (SAXS) techniques. Our results also proved that Uch37 oligomerized in solution and had very low activity against the fluorogenic substrate ubiquitin-7-amino-4-methylcoumarin (Ub-AMC) of de-ubiquitinating enzymes. Uch37Δ(Hb,Hc,KEKE), a truncation removal of the C-terminal extension region (residues 256-329) converted oligomeric Uch37 into a monomeric form that exhibited iso-peptidase activity comparable to that of a truncation-containing the Uch37 catalytic domain only. We also demonstrated that Rpn13C (Rpn13 residues 270-407) could disrupt the oligomerization of Uch37 by sequestering Uch37 and forming a Uch37-Rpn13 complex. Uch37 was activated in such a complex, exhibiting 12-fold-higher activity than Uch37 alone. Time-resolved SAXS (TR-SAXS) and FRET experiments supported the proposed mode of auto-inhibition and the activation mechanism of Uch37 by Rpn13. Rpn13 activated Uch37 by forming a 1:1 stoichiometric complex in which the active site of Uch37 was accessible to Ub.
Binding Sites ; Catalytic Domain ; Chromatography, Gel ; Crystallography, X-Ray ; Humans ; Membrane Glycoproteins ; chemistry ; genetics ; metabolism ; Nuclear Magnetic Resonance, Biomolecular ; Protein Binding ; Protein Conformation ; Protein Multimerization ; Scattering, Small Angle ; Ubiquitin Thiolesterase ; chemistry ; genetics ; metabolism ; Ultracentrifugation

【Objective】 To investigate the clinical effects of treatment of single-segment lumbar tuberculosis by oblique lateral interbody fusion with autologous iliac bone and percutaneous pedicle screw fixation. 【Methods】 We collected the clinical data of 47 patients with lumbar tuberculosis treated in The First Affiliated Hospital of Xi’an Jiaotong University from March 2017 to January 2020. Among them， 22 patients underwent oblique lateral interbody fusion with autologous iliac bone and percutaneous pedicle screw fixation （minimally invasive group） and 25 patients underwent open surgery combined anterior-debridement and posterior-fixation （control group）. The related data were collected， including gender， sex， body mass index （BMI）， systemic symptoms of tuberculosis， operation duration， intraoperative bleeding， postoperative drainage， hospital stay， complications， visual analogue score （VAS）， erythrocyte sedimentation rate （ESR）， and Oswestry disability index （ODI）. 【Results】 Baseline clinical characteristics did not significantly differ between the two groups （P>0.05）. Compared with control group， the minimally invasive group had shorter operation duration ［（188.64±18.59） min vs. （201.60±22.67） min］， less intraoperative blood loss ［（118.64±22.95） mL vs. （553.60±100.54） mL］， less postoperative drainage ［（134.55±36.48） mL vs. （291.20±61.53） mL］， and shorter hospitalization time ［（12.86±2.17） d vs. （15.80±3.03） d］ （all P<0.05）. However， there was no significant difference in fusion time or complication rate （P>0.05）. Compared with the preoperative ones， ESR， VAS score and ODI score significantly decreased and Cobb angle significantly increased in both groups （all P<0.001）. At postoperative 3 months， the VAS score was lower in the minimally invasive group than in control group ［（3.59±0.96） vs. （4.16±0.85）］ （P<0.05）. With regard to other characteristics， there was no significant difference between the two groups at the same point （P>0.05）. 【Conclusion】 Both minimally invasive technique and open surgery can achieve excellent clinical results， but the minimally invasive technique can reduce the surgical trauma and shorten the hospitalization time.