Design of PG-Surfactants Bearing Polyacrylamide Polymer Chain to Solubilize Membrane Proteins in a Surfactant-Free Buffer

The development of techniques capable of using membrane proteins in a surfactant-free aqueous buffer is an attractive research area, and it should be elucidated for various membrane protein studies. To this end, we examined a method using new solubilization surfactants that do not detach from membrane protein surfaces once bound. The designed solubilization surfactants, DKDKC12K-PAn (n = 5, 7, and 18), consist of two parts: one is the lipopeptide-based solubilization surfactant part, DKDKC12K, fand the other is the covalently connected linear polyacrylamide (PA) chain with different Mw values of 5, 7, or 18 kDa. Intermolecular interactions between the PA chains in DKDKC12K-PAn concentrated on the surfaces of membrane proteins via amphiphilic binding of the DKDKC12K part to the integral membrane domain was observed. Therefore, DKDKC12K-PAn (n = 5, 7, and 18) could maintain a bound state even after removal of the unbound by ultrafiltration or gel-filtration chromatography. We used photosystem I (PSI) from Thermosynecoccus vulcanus as a representative to assess the impacts of new surfactants on the solubilized membrane protein structure and functions. Based on the maintenance of unique photophysical properties of PSI, we evaluated the ability of DKDKC12K-PAn (n = 5, 7, and 18) as a new solubilization surfactant

男子大学駅伝選手における6 か月のピリオダイゼーションの筋疲労と免疫機能による評価

In order to assess 6-month periodisation of top university ekiden runner, the changes of muscle fatigue and immune functions of 17 male university ekiden runners were investigated in each training period. The investigation was carried out during the normal training period （6 months before the race）, before and after the intensive training camp period （3 or 4 months before the race）, at the start of the conditioning period （one month before the race） and at the end of the conditioning period （10 days before the race）. Investigation parameters were myogenic enzymes, serum opsonic activity （SOA） and serum superoxide dismutase （SOD）. Neither levels of myogenic enzymes nor immunoglobulins and complements showed any signifi cant changes in each period. The level of SOA signifi cantly decreased after the training camp compared to before, and tended to recover towards the race. SOD levels were signifi cantly higher after the training camp and at the conditioning period compared to before, which might be a reaction against the oxidative stress induced by training. Conclusion, the subjects had good physical management during the training periods prior to the race from the standpoint of muscle fatigue and immune functions. Furthermore, the parameters used in this study may be useful to assess runners’ physical condition during a long season of training

Construction and Characterization of Protein-Encapsulated Electrospun Fibermats Prepared from a Silica/Poly(γ-glutamate) Hybrid

Protein-encapsulated fibermats are an attractive platform for protein-based bioactive materials. However, the choice of methods is still limited and not applicable to a wide range of proteins. In this study, we studied new polymeric materials for constructing protein-encapsulated fibermats, in which protein molecules are encapsulated within the nanofibers of fibermats without causing deleterious changes to protein structure or function. We constructed a protein-encapsulated fibermat using the poly­(γ-glutamate) (PGA)/(3-glycidyloxypropyl)-trimethoxysilane (GPTMS) hybrid as a precursor for electrospinning. Because the PGA/GPTMS hybrid is water-soluble, protein molecules can be added to the precursor in an aqueous solution, significantly enhancing protein stability. Polycondensation during electrospinning (in-flight polycondensation) makes the obtained fibermats water-insoluble, which stabilizes the fibermat structure such that it is resistant to degradation in aqueous buffer. The molecular structure of the PGA/GPTMS hybrid gives rise to unique molecular permeability, which alters the selectivity and specificity of biochemical reactions involving the encapsulated enzymes; lower molecular-weight (MW) substrates can permeate the nanofibers, promoting enzyme activity, but higher MW substrates such as inhibitor peptides cannot permeate the nanofibers, suppressing enzyme activity. We present an effective method of encapsulating bioactive molecules while maintaining their structure and function, increasing the versatility of electrospun fibermats for constructing various bioactive materials