Tokyo univ. ef Tech. Recently, thcre advances the collaboratien ef magnetonics and ]ife sciellcc fields. in this research, we focused on iron storage protein ferritin, which cncapsu]ate iron oxide in the budy, A cavity of fr-g nin in a diameteT can be obtained after the rernoval of iron oxide froi-fenitin. Wd cxpdv L that magnetie material can be encapsulated in this cavity. Thcre havc bccn reported the preparation of magnetite cneapsulating fcrritin, hewever it could not be adsorbed by a bar

more »

... gnct bccause the e]cupsulated sizc ot' mngnetite is in the suparparamugnetic size ramge. Herc. wc focused Dn cobalt ferrite us the candidate of encapsulated magnetic matcrial, Because cobalt ferrite possesscs largc tmagnctocrysta11ime anisotropy. ratheT high rnagnetization can be expected whell it is e]icupsulatcd in the cavity of ferritin. in this research. cobalt fcrrlte ultra fine purticle, which ls as small as can be encapsulated in the cavity of fenitin, wus prepared by chemical coprecipitation melhod und crystal structurc and thc morphologic properties were measured by Xray diffraction analysis and transmissi{m eLectron mierescope. respcetivcly. The magnetization of cobalt ferrite ultra flnc particle was measllred with vibrating sample magnetometer and 6-8 nm cobalt fenite ultru finc particlc showed 20ij40 emutg uf magnetization, Funhcrmorc, after the removal of iron exides fu)m ferritin and the encapsulation of cobult fenite wtts utt:mptcd, The change of UVtvis spectrum after the reaction indicate the cncapsulation ol' cobalt ferrile in the cavity offerritin. IP142Sitc-sclectiye deposition of ferritin on the pattcrned silicon substrates OAkiraYimiazak1,HirekeFukano.HideyukiYeshimura Dept.ofPhysics,MeijiUniveTsity To utilize the function of protein molecules, many reports regarding to the fixation of proteins on solid substrates have becn published rceently. Mest of these reports empleyed hydrophobic or electrostatic intcractions instead of spectELc olle such as antigen-antibody bindings. Here we demenstrate setective fixation of horse spleen ferritin on silieon sllbstrates usi"g antibedy against horsc splcen t'erritin. Ferri[in is a spherieal proLein with a cavity inside the molecule and it is knewn to store iren oxide in the cHvity. The inner and outer dianictcrs of ferrithi ure 7 und 13nm, respectively. Horse spleen ferritin and its antibody exrracted ftt)m rabbit untiserum were purchased frorn Sigma. The pattem was fabricatcd using thermalry oxidized silicon substrate with resist layer by electren beim CEB) or photo lithography.The substrutes pretreuted 1]y Sigmacote (Sigma) were submcrgcd in anti-ferritin solution for S min. Thcsc werc rinsed and then dipped in ferritin solution for 1 min. After this procedure, patterned resist layer on the substratc was remuved by organic solvcnt. We used SEM and AFM to inspect distributiem of fcnitin on the substrate and ohserved fenitins forming the pattem on the substrate, This rcsult indicates that ttnti-ferritin adsorbcd on thc substrate can selectivety beund fenitin and make patterns. This methed will be ttpplieablc for selective deposition ef nafiepartic]es that can be a catalyst for gro"'th of nanotube$. IP143LAHTH: A, designed hetii-tum-helix protein with high thermal stabilityOTakuMatsuba,NaokiUmeda,SatoshiAkanuma,AkihikoYaiuagishi Dcpt. ofMolecular Biology, Tekyo Univ. Pharn. and I.ife Sci. Taking advantage of thc ability ef bielogical systems, such as protein, is ef great interest in the fabrieatioll of novel functienul mat6rials and micro-{nano-) devices. Individual pretehis often show cxtrcmely specific recognition to other molecutes and therefore can be useful teels for development of biomimctic approaehes to creatc llcw intcraetions between organic and inorganic materials. Recent studies to produce artificial proteins thar specifically bind to inorganic muteriuls havc done mainly with smatl peptides and antibo[Lies, In this study, we designed und synthesized an alternative scaffold that would auquirc thc ability to bind inorganic materials such as metals. The clesjgn of 4g-residue polypeptide chain was based on the C-terniinal seque"ce of E. coli iac repTessor, which is involvcd in its ± burL helix-bundlc domain, Thus, the polypeptide chain forms a helix-tum-helix and designated us 1.AHTH (Ltc repressor derived belix-!uni-helix). Far-UV CD unalysis fnr LAHTH showed a spectmm typical to helix-rieh protcins. Thcnna] denaturation study showed that, although LAHTH was designcd bascd on the sequence of E, ['oli pretein, thc arti[ELcial hclix-turn-helix protein is extremely thermostable (T . = 81 "C). An ana]ytica] gel fi1tration xvus canied out te investigate the extent of intermeleculur association f'or I.AHTH, indicating that LAHTH djmcrizes in selution to form a fQur-helix bundle te seme extent. wr are currentiy designjpg new protein molecules that can specifically interact with mctals. using LAHTH as thc scaffbld. IP144HyperthermQphilic trfinslation systcm in the common allcestor: Analysis ef ancestral mutants of G]yRS of the TlhermLts thermophilzas. OHideaki shimizui, Shin-ichi Yokobori', Takazoshi Ohkurii'2, Takashi YOkogawa], KazuyaNishikawa',AkihikoYainugishiL tDepartmcnt of Molcculur Biology, Tbkyo University of Pharrnacy and Life Scicncc. 2Prcscnt address/ Gradurate Scool ef Phurrnaceatical Scicnccs, Kyushu Univcrsity, ]Dcpartment ef Biomolecular Science, Faeulty of Enginecring, Gifu Unlverslty Based on phylogenetic analysis of 16S and 18S rRNA sequences, the common ancestor of all organisms {Cemtllonete) was prepesed te be a hyperthermophile. We have tested this hypothesis using enzymes with ancestral residues that baye been inferred ffom molecular phylogenetie analysis. The uiicestral mutant 3isoprepylinalate dehydr[)genases (IPMDHs) and isncitralc dehtdrogenases <ICDHs), tht otiginal enzymes being involved in metabolism system, showed higher thermal stability than the wild type enzymes. These results urc consistent with the hyperthermeph-c common anccstor hypothesis (1-3).ln thjs werk, we have extended the experiments to the enzyme in translation system, glycyl-tRNA synthetase (GtyRS). The maximurn-likclihood tree of tt, type G]yRS was constractcd, Then, thc sequence ef ancestral GtyRS wus iderred. The anccstral residues were introdueed inte Z thermophitMs GlyRS. Eight mutants weTe construcrcd, cxpressed and purit]'ed, Sjx mutants aquired higher thermostability than the wi]d-type enzyme. The result suggests that thc Con}monete had the hypenhcrmophilic tratislation system.(1)