Zervamicin IIB is a 16 amino acid peptaibol that forms voltage dependent ion channels with multilevel conductance states in planar lipid bilayers and vesicular systems. Stability of the hinge region and intermolecular interactions were investigated in the N- and C-terminally spin-labelled peptide analogues. Intermolecular and intramolecular paramagnetic enhancement indicates that zervamicin behaves as a rigid helical rod in methanol solution. There are no high amplitude hinge-bending motions, and the peptaibol is monomeric up to concentration 1.5 mM. Stability of the hinge region illustrates the helix stabilising propensity of the Pro residue in membrane mimic environments and implies absence of significant conformational rearrangement due to voltage peptaibol activation.
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http://dx.doi.org/10.1016/j.bbrc.2004.10.115 | DOI Listing |
Enzymatic asymmetric synthesis of l-phenylglycine by amino acid dehydrogenases has potential for industrial applications; however, this is hindered by their low catalytic efficiency toward high-concentration substrates. We identified and characterized a novel leucine dehydrogenase (LeuDH) with a high catalytic efficiency for benzoylformic acid via directed metagenomic approaches. Further, we obtained a triple-point mutant LeuDH-EER (D332E/G333E/L334R) with improved stability and catalytic efficiency through the rational design of distal loop 13.
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January 2025
School of Emergency Management and Safety Engineering, China University of Mining & Technology, Beijing, 100083, China.
To address limitations of traditional inclinometers and height sensors in determining the posture and support height of hydraulic supports in coal mining, we propose a novel method predicated on travel measurements of the leg and tail beam cylinders. This method calculates the posture and height of hydraulic supports in mechanized mining. By conducting meticulous kinematic analysis of the hydraulic supports, a skeleton model of the main structural parameters of the hydraulic support was constructed.
View Article and Find Full Text PDFCureus
December 2024
Orthopedic Surgery, Sengkang General Hospital, Singapore, SGP.
Background: Femoral condyle insufficiency fractures following total knee arthroplasty (FCIF-TKA) are rare but significant complications. These fractures, characterized by atraumatic bone insufficiency near the femoral component, present unique challenges in postoperative care, often necessitating femoral component revision.
Methods: This study retrospectively reviewed 835 primary total knee arthroplasties performed by a single surgeon, identifying six cases of FCIF-TKA.
J Am Coll Cardiol
January 2025
Baylor Heart and Vascular Institute, Dallas, Texas, USA; Imperial College, London, United Kingdom.
Patient-reported health status is an important assessment of patients with heart failure, but current approaches have substantial methodological and analytical limitations. Changes in the Kansas City Cardiomyopathy Questionnaire (KCCQ) are commonly presented as a measure of the effect of drugs and devices, most often as the between-group difference in population means or as the odds of showing threshold changes of 5, 10, 15, and 20 points. However, the presentation of mean differences is based on statistical assumptions that are routinely violated in most trials.
View Article and Find Full Text PDFBiochim Biophys Acta Biomembr
January 2025
Land and Food Systems, University of British Columbia, Vancouver, Canada; Faculty of Agricultural, Life and Environmental Sciences, University of Alberta, Edmonton, Canada. Electronic address:
The Solanum tuberosum (common potato) plant specific insert (StPSI) is an antimicrobial protein domain that exhibits membrane-disrupting and membrane-fusing activity upon dimerization at acidic pH, activity proposed to involve electrostatic attraction and membrane anchoring mediated by specific positively-charged and conserved tryptophan residues, respectively. This study is the first to employ an in silico mutagenesis approach to clarify the structure-function relationship of a plant specific insert (PSI), where ten rationally-mutated StPSI variants were investigated using all-atom and coarse-grained molecular dynamics. The tryptophan (W) residue at position 18 (W18) of wild-type StPSI was predicted to confer structural flexibility to the dimer and mediate a partial separation of the assembled monomers upon bilayer contact, while residues including W77 and the lysine (K) residue at position 83 (K83) were predicted to stabilize secondary structure and influence association with the model membrane.
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