The flagellar filament enables bacteria to swim by functioning as a helical propeller. The filament is a supercoiled assembly of a single protein, flagellin, and is formed by 11 protofilaments arranged in a circle. Bacterial swimming and tumbling correlate with changes of the various helical structures, called polymorphic transformation, that are determined by the ratios of two distinct forms of protofilaments, the L and R types. The polymorphic transformation is caused by transition of the protofilament between L and R types. Elucidation of this transition mechanism has been addressed by comparing the atomic structures of L-and R-type straight filaments or using massive molecular dynamic simulation. Here, we found amino acid residues required for the transition of the protofilament using fliC-intragenic suppressor analysis. We isolated a number of revertants producing supercoiled filaments from mutants with straight filaments and identified the second-site mutations in all of the revertants. The results suggest that Asp107, Gly426, and Ser448 and Ser106, Ala416, Ala427, and Arg431 are the key residues involved in inducing supercoiled filaments from the R-and the L-type straight filaments, respectively. Considering the structures of the R-and L-type protofilaments and the relationship between the rotation of the flagellar motor and the polymorphic transformation, we propose that Gly426, Ala427, and Arg431 contribute to the first stage of the transition and that Ser106, Asp107, and Ala416 play a role in propagating the transitions along the flagellar filament.

JapanGeneral IncorporatedAssociation metabolisrn of lipoproteins and their uptake in tissues. Some mutations in apo[ipoproteins are re]ated te inheritable disease. In this work, we studied physica] properties of amino acid mutatjons in two groups: mutations with and without disease suseeptibility in apo[ipoproteins. The analysis was carried out by two steps/ First, we enumerated peaks of MR-index plots ftom ainino aeid sequences, and the mutations which changed the positien of the MR-index peak were used for further analysis, Second, we calculated the avcrage hydrophobieity and charge density of seven residues, and changes in the rnagnitude as well as the position ofMR-index peaks. MR-index is an index that estimates allergen-specific amino acid sequence and

always poputated but we presume we have resol}ed stator rotor inieraLtJons in the passive (foked) rotdtion in the V. doTnmn possibly Leupled to proton translecaticrn 3p-132-msma:-t>yox7vftt(X(:fte(:ttbkd>t6 Stroke size of smgle skeletal myosms changes w]th loads MbtoghtKZva a] andH)deo HigrvLht (lyn DcptPfpsiLs CraduateShoet ofS"en(e Vmv of7hlyojPor" and dlsplacernLnt generdted by myos)n IT motors dppearLd to be vvidely vaned between lahoratoncs OnL ot 1imitanong associated with these mcomsistent resutts is attributed to the nonprocessive property of wyosins ll Thus in ordci to avoid non pro"bsLv]ty "e synth"i7ed spdrse skclLtal myosin !od cofilaments wheTe 2 5 myosin melecutes can mteraLt with an actm At low rm] concentration we observed processwe and stepwise movemenis generated by myosms whiLh unitary step gizL changLd from 7nrn m srndll lead to Snm in high load)rom the dwell tlme analysis indiyidua] steps were 1ikely gLnerated by one of myosin mejeeules distmbuted along myosm rod Lefilamevt aeLording to Poiggon btatigtiLs ThL sintiness ot gingTe myosins vas estimated by the force extenslon curve ef smgle rnyosms in the absence of MP The btiffiiess was high vhen myosms are stretched but mteTestmgly smaller when shortened Combmed with these iLsu]ts the "milar step giLeg obserxcd frorn defferent nuinbers of myosin meleeule can be mterpreted as the situation that the acttve myostn pnmarily contnbutes to the working stroke while other post btroke m}ogins barely Lontnbate to the dTag force agalnst thL " otking strokL geneiainon Also the decreage m the step size with loadg ig hkely due to the stretchmg ofthe elasTic poiuon of rr",osin that counteracts igamst the-erinng streke generated by theattlsLnryosln ibmoko tlfijata O) IZikeryuki Kbto (l) Tinkasin fitJn rJ O Ifidny,uki nydintvunamt M S) and Ke"rhi Namha any (J emdvatt schooi ofFrontier thogcienccf Ovakc: Lmversity 2 tCCIRP Q)namtc VbneAdachrne Prnyect JS7 3 Oinna"a inytltutL of saren" and lechnorogy Promotlon Cbrporation inmalResear[h PrTijcct Many bactema b-Lm b} rotating flagelld which functions as hehLdl proptllLTs