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141.
142.
Lin TH Huang YC Chin ML Chen YC Jeng HH Lin FM Shiao MS Horiuchi A Greengard P Nairn AC Huang HB 《Journal of biomolecular NMR》2004,28(4):413-414
143.
Liao YD Jeng JC Wang CF Wang SC Chang ST 《Protein science : a publication of the Protein Society》2004,13(7):1802-1810
The removal of N-terminal translation initiator Met by methionine aminopeptidase (MetAP) is often crucial for the function and stability of proteins. On the basis of crystal structure and sequence alignment of MetAPs, we have engineered Escherichia coli MetAP by the mutation of three residues, Y168G, M206T, Q233G, in the substrate-binding pocket. Our engineered MetAPs are able to remove the Met from bulky or acidic penultimate residues, such as Met, His, Asp, Asn, Glu, Gln, Leu, Ile, Tyr, and Trp, as well as from small residues. The penultimate residue, the second residue after Met, was further removed if the antepenultimate residue, the third residue after Met, was small. By the coexpression of engineered MetAP in E. coli through the same or a separate vector, we have successfully produced recombinant proteins possessing an innate N terminus, such as onconase, an antitumor ribonuclease from the frog Rana pipiens. The N-terminal pyroglutamate of recombinant onconase is critical for its structural integrity, catalytic activity, and cyto-toxicity. On the basis of N-terminal sequence information in the protein database, 85%-90% of recombinant proteins should be produced in authentic form by our engineered MetAPs. 相似文献
144.
Upregulation of endothelin-1 binding in tissues of salt-loaded stroke-prone spontaneously hypertensive rats 总被引:3,自引:0,他引:3
Upon maintained on a 1% NaCl drinking solution beginning at 7 weeks of age, the stroke-prone spontaneously hypertensive rat (SHRsp) developed severe hypertension and stroke; most died by 16 weeks. The mechanism by which these diseases evolve remains unclear. Endothelin-1 (ET-1) is a potent, peptidic vasoconstrictor and is implicated in the pathogenesis of various cardiovascular, renal, and central nervous system diseases. The purpose of the present study was to compare the binding of [125I]ET-1 to the brain, heart, kidney, liver, and spleen membrane preparations of 16-week-old SHRsp and age-matched normotensive Wistar-Kyoto rats (WKY). The KD values for [125I]ET-1 binding to the corresponding tissues of the two strains were not significantly different, except in the brain (SHRsp: 17 +/- 1 pM; WKY: 24 +/- 1 pM). In contrast, the Bmax values measured in the brain, heart, kidney, and liver of SHRsp were 1.5- to 2.1-fold greater than those of their WKY counterparts. Competition of [125I]ET-1 binding to the membrane preparations by the specific ETA receptor antagonist BQ-123 or the specific ETB receptor agonist sarafotoxin S6c revealed a similar proportion of ETA and ETB receptor subtypes in the corresponding tissues of the two rat strains. These results indicate that ET-1 binding is upregulated in SHRsp and suggest that ET-1 may play a pathophysiological role in this animal model of genetic hypertension. 相似文献
145.
146.
S Hoare J A Copland Z Strakova K Ives Y J Jeng M R Hellmich M S Soloff 《The Journal of biological chemistry》1999,274(40):28682-28689
As the oxytocin receptor plays a key role in parturition and lactation, there is considerable interest in defining its structure/functional relationships. We previously showed that the rat oxytocin receptor transfected into Chinese hamster ovary cells was coupled to both G(q/11) and G(i/o), and that oxytocin stimulated ERK-2 phosphorylation and prostaglandin E(2) synthesis via protein kinase C activity. In this study, we show that deletion of 51 amino acid residues from the carboxyl terminus resulted in reduced affinity for oxytocin and a corresponding rightward shift in the dose-response curve for oxytocin-stimulated [Ca(2+)](i). However, oxytocin-stimulated ERK-2 phosphorylation and prostaglandin E(2) synthesis did not occur in cells expressing the truncated receptor. Oxytocin also failed to increase phospholipase A activity or activate protein kinase C, indicating that the mutant receptor is uncoupled from G(q)-mediated pathways. The Delta51 receptor is coupled to G(i), as oxytocin-stimulated Ca(2+) transients were inhibited by pertussis toxin, and a Gbetagamma sequestrant. Preincubation of Delta51 cells with the tyrosine kinase inhibitor, genistein, also blocked the oxytocin effect. A Delta39 mutant had all the activities of the wild type oxytocin receptor. These results show that the portion between 39 and 51 residues from the COOH terminus of the rat oxytocin receptor is required for interaction with G(q/11), but not G(i/o). Furthermore, an increase in intracellular calcium was generated via a G(i)betagamma-tyrosine kinase pathway from intracellular stores that are distinct from G(q)-mediated inositol trisphosphate-regulated stores. 相似文献
147.
Twenty-six strains of Borrelia burgdorferi sensu lato were subjected to polymerase chain reaction (PCR)-based restriction fragment length polymorphism (RFLP) analysis for assessing the sequence divergence of rpoD gene encoding the primary sigma factor. Four and five RFLP patterns were observed from two fragments of rpoD gene. Sequence analysis of a subgenic fragment covering region 1 through 4 from 13 strains of Borrelia burgdorferi s. l. revealed that 21 of 450 deduced amino acid residues were diverged. These results indicate that the sequence heterogeneity of rpoD is present in different strains of Borrelia burgdorferi s. l., and agreed well with the current classification of genospecies. 相似文献
148.
149.
Adam J Carlton JingYi Jeng Fiorella C Grandi Francesca De Faveri Federico Ceriani Lara De Tomasi Anna Underhill Stuart L Johnson Kevin P Legan Corn J Kros Guy P Richardson Mirna Mustapha Walter Marcotti 《The EMBO journal》2023,42(4)
Sensory‐independent Ca2+ spiking regulates the development of mammalian sensory systems. In the immature cochlea, inner hair cells (IHCs) fire spontaneous Ca2+ action potentials (APs) that are generated either intrinsically or by intercellular Ca2+ waves in the nonsensory cells. The extent to which either or both of these Ca2+ signalling mechansims are required for IHC maturation is unknown. We find that intrinsic Ca2+ APs in IHCs, but not those elicited by Ca2+ waves, regulate the maturation and maintenance of the stereociliary hair bundles. Using a mouse model in which the potassium channel Kir2.1 is reversibly overexpressed in IHCs (Kir2.1‐OE), we find that IHC membrane hyperpolarization prevents IHCs from generating intrinsic Ca2+ APs but not APs induced by Ca2+ waves. Absence of intrinsic Ca2+ APs leads to the loss of mechanoelectrical transduction in IHCs prior to hearing onset due to progressive loss or fusion of stereocilia. RNA‐sequencing data show that pathways involved in morphogenesis, actin filament‐based processes, and Rho‐GTPase signaling are upregulated in Kir2.1‐OE mice. By manipulating in vivo expression of Kir2.1 channels, we identify a “critical time period” during which intrinsic Ca2+ APs in IHCs regulate hair‐bundle function. 相似文献
150.
Chana JS Chang YM Wei FC Shen YF Chan CP Lin HN Tsai CY Jeng SF 《Plastic and reconstructive surgery》2004,113(1):80-87
Thirteen patients with large ameloblastomas of the mandible underwent segmental mandibulectomy and immediate reconstruction, with simultaneous placement of osseointegrated implants. All patients received palatal mucosal grafts around the dental implants 6 to 10 months after surgical treatment and received implant-supported prostheses another 1 to 2 months later. There were five female and eight male patients, with a mean age of 32 years (range, 17 to 50 years). The mean length of the mandibular defect was 8.8 cm (range, 5 to 13 cm). All free fibula flap procedures were successful, with no reexplorations or partial flap losses. There was no clinical or radiographic evidence of failure during the osseointegration process for any implant. With functional occlusal loading, the marginal bone loss around the implants was less than 1.5 mm in a mean follow-up period of 40 months (range, 18 to 70 months). There were no recurrences during that time. The technique described allows improved access to the bone at the time of reconstruction, immediate assessment of alveolar ridge relationships, and accurate fixation of the implant-fibula construct. The advantages of this procedure include a reduced risk of recurrence with segmental resection, reliable mandibular reconstruction, and reduction of the number of surgical procedures, allowing full oral rehabilitation in a shorter time. It is concluded that segmental mandibulectomy and immediate vascularized fibula osteoseptocutaneous flap reconstruction, with simultaneous placement of osseointegrated implants, represent an ideal treatment method for large ameloblastomas of the mandible. 相似文献