The one-carbon carrier methylofuran from Methylobacterium extorquens AM1 contains a large number of alpha- and gamma-linked glutamic acid residues

Methylobacterium extorquens AM1 uses dedicated cofactors for one-carbon unit conversion. Based on the sequence identities of enzymes and activity determinations, a methanofuran analog was proposed to be involved in formaldehyde oxidation in Alphaproteobacteria. Here, we report the structure of the cofactor, which we termed methylofuran. Using an in vitro enzyme assay and LC-MS, methylofuran was identified in cell extracts and further purified. From the exact mass and MS-MS fragmentation pattern, the structure of the cofactor was determined to consist of a polyglutamic acid side chain linked to a core structure similar to the one present in archaeal methanofuran variants. NMR analyses showed that the core structure contains a furan ring. However, instead of the tyramine moiety that is present in methanofuran cofactors, a tyrosine residue is present in methylofuran, which was further confirmed by MS through the incorporation of a C-13-labeled precursor. Methylofuran was present as a mixture of different species with varying numbers of glutamic acid residues in the side chain ranging from 12 to 24. Notably, the glutamic acid residues were not solely gamma-linked, as is the case for all known methanofurans, but were identified by NMR as a mixture of alpha- and gamma-linked amino acids. Considering the unusual peptide chain, the elucidation of the structure presented here sets the basis for further research on this cofactor, which is probably the largest cofactor known so far

A longitudinal analysis of gross motor coordination in overweight and obese children versus normal-weight peers

BACKGROUND: The relationship of childhood overweight (OW) and obesity (OB) with motor skill and coordination is gaining due attention; however, longitudinal evidence is currently lacking. OBJECTIVE: The dual purpose of this study was (1) to investigate the short-term evolution in the level of gross motor coordination according to children's weight status, and (2) to identify those factors predicting their gross motor coordination performance over a 2-year interval. SUBJECTS: Participants were 50 children with OW, including 8 with OB (aged 6-10 years at baseline, with 52% boys), and 50 with normal-weight (NW) matched for gender and age. MEASUREMENTS: Anthropometrics (body height, body weight, body mass index (BMI), %body fat) and level of gross motor coordination (Körperkoordinationstest für Kinder, KTK) were assessed in 2007 (baseline) and 2 years later in 2009 (follow-up). At baseline, participants completed a survey based on the Flemish Physical Activity Questionnaire (FPAQ) to obtain socio-demographic information and to determine physical activity levels in diverse domains. RESULTS: The evolution in the level of gross motor coordination over time was strongly related to children's weight status. Participants in the NW group showed more progress than their OW/OB peers, who demonstrated significantly poorer performances. Accordingly, between-group differences in KTK outcomes (that is, raw item scores and total motor quotient) became more evident over time. Multiple linear regression analysis further indicated that, in addition to BMI per se (negative predictor), participation in organized sports within a sports club (positive predictor) determines gross motor coordination performance(s) 2 years later. CONCLUSION: Our results provide conclusive evidence for an increasingly widening gap of OW/OB children's gross motor coordination relative to NW peers across developmental time in the absence of targeted initiatives. Special attention is thus needed for OW/OB children, especially for those not practicing sports in a club environment, in terms of motor skill improvement to promote regular participation in physical activit