On the binding mechanism of the peptide receptor of the oligopeptide transport system of Lactococcus lactis

Lactococcus lactis degrades exogenous proteins such as β-casein to peptides of 4–30 amino acids, and uses these as nitrogen sources. The binding protein or receptor (OppA(Ll)) of the oligopeptide transport system (Opp) of L.lactis has the unique capacity to bind peptides from five up to at least 20 residues. To study the binding mechanism of OppA(Ll), nonameric peptides were used in which the cysteine at position 1, 3, 4, 5, 6, 7 or 9 was selectively labeled with either bulky and non-fluorescent or bulky and fluorescent groups. Also, nonameric peptides with a non-natural residue, azatryptophan, at positions 3 or 7 were used. The fluorescence of azatryptophan reports on the polarity of the environment. The studies indicate that the binding protein encloses the first six amino acids of the peptide, whereas the remaining residues stick out and interact with the surface of the binding protein. The peptide binding mechanism of OppA(Ll) is discussed in relation to known three-dimensional structures of members of this class of proteins, and an adaptation of the general binding mechanism is proposed

Human anti-MuSK IgG4 autoantibodies cause myasthenia gravis in immunodeficient mice

Neurological Motor Disorder

Body mass index and complications following major gastrointestinal surgery: A prospective, international cohort study and meta-analysis

Aim Previous studies reported conflicting evidence on the effects of obesity on outcomes after gastrointestinal surgery. The aims of this study were to explore the relationship of obesity with major postoperative complications in an international cohort and to present a metaanalysis of all available prospective data. Methods This prospective, multicentre study included adults undergoing both elective and emergency gastrointestinal resection, reversal of stoma or formation of stoma. The primary end-point was 30-day major complications (Clavien–Dindo Grades III–V). A systematic search was undertaken for studies assessing the relationship between obesity and major complications after gastrointestinal surgery. Individual patient meta-analysis was used to analyse pooled results. Results This study included 2519 patients across 127 centres, of whom 560 (22.2%) were obese. Unadjusted major complication rates were lower in obese vs normal weight patients (13.0% vs 16.2%, respectively), but this did not reach statistical significance (P = 0.863) on multivariate analysis for patients having surgery for either malignant or benign conditions. Individual patient meta-analysis demonstrated that obese patients undergoing surgery formalignancy were at increased risk of major complications (OR 2.10, 95% CI 1.49–2.96, P < 0.001), whereas obese patients undergoing surgery for benign indications were at decreased risk (OR 0.59, 95% CI 0.46–0.75, P < 0.001) compared to normal weight patients. Conclusions In our international data, obesity was not found to be associated with major complications following gastrointestinal surgery. Meta-analysis of available prospective data made a novel finding of obesity being associated with different outcomes depending on whether patients were undergoing surgery for benign or malignant disease