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Fei Li

Publications and source records attributed to Fei Li.

At least 73 records · Page 4Linked to original sources
PubMed2004

C-peptide corrects endoneurial blood flow but not oxidative stress in type 1 BB/Wor rats.

Oxidative stress and neurovascular dysfunction have emerged as contributing factors to the development of experimental diabetic neuropathy (EDN) in streptozotocin-diabetic rodents. Additionally, depletion of C-peptide has been implicated in the pathogenesis of EDN, but the mechanisms of these effects have not been fully characterized. The aims of this study were therefore to explore the effects of diabetes on neurovascular dysfunction and indexes of nerve oxidative stress in type 1 bio-breeding Worcester (BB/Wor) rats and type 2 BB Zucker-derived (ZDR)/Wor rats and to determine the effects of C-peptide replacement in the former. Motor and sensory nerve conduction velocities (NCVs), hindlimb thermal thresholds, endoneurial blood flow, and indicators of oxidative stress were evaluated in nondiabetic control rats, BB/Wor rats, BB/Wor rats with rat II C-peptide replacement (75 nmol C-peptide.kg body wt(-1).day(-1)) for 2 mo, and diabetes duration-matched BBZDR/Wor rats. Endoneurial perfusion was decreased and oxidative stress increased in type 1 BB/Wor rats. C-peptide prevented NCV and neurovascular deficits and attenuated thermal hyperalgesia. Inhibition of nitric oxide (NO) synthase, but not cyclooxygenase, reversed the C-peptide-mediated effects on NCV and nerve blood flow. Indexes of oxidative stress were unaffected by C-peptide. In type 2 BBZDR/Wor rats, neurovascular deficits and increased oxidative stress were unaccompanied by sensory NCV slowing or hyperalgesia. Therefore, nerve oxidative stress is increased and endoneurial perfusion decreased in type 1 BB/Wor and type 2 BBZDR/Wor rats. NO and neurovascular mechanisms, but not oxidative stress, appear to contribute to the effects of C-peptide in type 1 EDN. Sensory nerve deficits are not an inevitable consequence of increased oxidative stress and decreased nerve perfusion in a type 2 diabetic rodent model.

Animals↗
PubMed2004

[The expression of Cyclin D1 modulated by somatotropin on human pancreas cancer cell lines Bxpc-3].

OBJECTIVE: To observe the growth effect of somatostapin on human pancreas cancer lines Bxpc-3. METHODS: The Bxpc-3 pancreas cancer cells were treated with Somatotropin. The cells hyperplasia were detected by MTT and were observed apoptosis cells determinated quantitatively by TUNEL, quantify immune fluoresence double marked the proliferation cells and apoptosis cells, the expression of Cyclin D1 detected by immunohistochemical. RESULTS: The growth effect of pancrea cancer cells were limited by 10(-7) M, 10(-8) M, 10(-9) M Somatotropin on 2 day. The limited effect was decreased from 3 day. The cells proliferation were increased by somotostapin on 4day to 5day. The relationship between the expression of Cyclin D1 and apoptosis was negative correlation and the cells hyperplasia was positive correlation in Bxpc-3 cell line. CONCLUSION: From the cell study we knew the expression of Cyclin D1 reflected the prolefiration of pancreas cancer cells.

Apoptosis↗
PubMed2004

CD34+CD38- hematopoietic precursors derived from human embryonic stem cells exhibit an embryonic gene expression pattern.

Gene expression patterns of CD34(+)CD38(-) cells derived from human embryonic stem cells (ESCs) were compared with those of cells isolated from adult human bone marrow (BM) using microarrays; 1692 and 1494 genes were expressed at levels at least 3-fold above background in cells from BM and ESCs, respectively. Of these, 494 showed similar levels of expression in cells from both sources, 791 genes were overexpressed in cells from BM (BM versus ESCs, at least 2-fold), and 803 genes were preferentially expressed in cells from ESCs (ESCs versus BM, at least 2-fold). The message of the flt-3 gene was markedly decreased in cells from ESCs, whereas there was substantial flt-3 expression in cells from BM. High levels of embryonic epsilon-globin expression were observed-but no adult beta-globin message-in CD34(+)CD38(-) cells from ESCs, whereas high levels of beta-globin expression-but no embryonic epsilon-globin message-could be detected in cells from BM. Furthermore, high levels of major histocompatibility complex (MHC) gene expression were demonstrated in cells from BM but very low levels of MHC message in corresponding cells from ESCs. These observations demonstrate that CD34(+)CD38(-) cells derived from ESCs correspond consistently to an early developmental stage at which the yolk sac and fetal liver are the primary sites of hematopoiesis.

ADP-ribosyl Cyclase↗
PubMed2004

Mutations in acetylcholinesterase associated with insecticide resistance in the cotton aphid, Aphis gossypii Glover.

Two acetylcholinesterase genes, Ace1 and Ace2, have been fully cloned and sequenced from both organophosphate-resistant and susceptible clones of cotton aphid. Comparison of both nucleic acid and deduced amino acid sequences revealed considerable nucleotide polymorphisms. Further study found that two mutations occurred consistently in all resistant aphids. The mutation F139L in Ace2 corresponding to F115S in Drosophila acetylcholinesterase might reduce the enzyme sensitivity and result in insecticide resistance. The other mutation A302S in Ace1 abutting the conserved catalytic triad might affect the activity and insecticide sensitivity of the enzyme. Phylogenetic analysis showed that insect acetylcholinesterases fall into two subgroups, of which Ace1 is the paralogous gene whereas Ace2 is the orthologous gene of Drosophila AChE. Both subgroups contain resistance-associated AChE genes. To avoid confusion in the future work, a nomenclature of insect AChE is also suggested in the paper.

Acetylcholinesterase↗
PubMed2004

Structure and topology of the transmembrane domain 4 of the divalent metal transporter in membrane-mimetic environments.

The divalent metal transporter (DMT1) is a 12-transmembrane domain protein responsible for dietary iron uptake in the duodenum and iron acquisition from transferrin in peripheral tissues. The transmembrane domain 4 (TM4) of DMT1 has been shown to be crucial for its biological function. Here we report the 3D structure and topology of the DMT1-TM4 peptide by NMR spectroscopy with simulated annealing calculations in membrane-mimetic environments, e.g. 2,2,2-trifluoroethanol and SDS micelles. The 3D structures of the peptide are similar in both environments, with nonordered and flexible N- and C-termini flanking an ordered helical region. The final set of the 16 lowest energy structures is particularly well defined in the region of residues Leu9-Phe20 in 2,2,2-trifluoroethanol, with a mean pairwise root mean square deviation of 0.23 +/- 0.10 A for the backbone heavy atoms and 0.82 +/- 0.17 A for all heavy atoms. In SDS micelles, the length of the helix is dependent on pH values. In particular, the C-terminus becomes well-structured at low pH (4.0), whereas the N-terminal segment (Arg1-Gly7) is flexible and poorly defined at all pH values studied. The effects of 12-doxylPtdCho spin-label and paramagnetic metal ions on NMR signal intensities demonstrated that both the N-terminus and helical region of the TM4 are embedded into the interior of SDS micelles. Unexpectedly, we observed that amide protons exchanged much faster in SDS than in 2,2,2-trifluoroethanol, indicating that there is possible solvent accessibility in the structure. The paramagnetic metal ions broaden NMR signals from residues both situated in aqueous phase and in the helical region. From these results we speculate that DMT1-TM4s may self-assemble to form a channel through which metal ions are likely to be transported. These results might provide an insight into the structure-function relationship for the integral DMT1.

Amino Acid Sequence↗
PubMed2004

Role of poly(ADP-ribose) polymerase activation in diabetic neuropathy.

Oxidative and nitrosative stress play a key role in the pathogenesis of diabetic neuropathy, but the mechanisms remain unidentified. Here we provide evidence that poly(ADP-ribose) polymerase (PARP) activation, a downstream effector of oxidant-induced DNA damage, is an obligatory step in functional and metabolic changes in the diabetic nerve. PARP-deficient (PARP(-/-)) mice were protected from both diabetic and galactose-induced motor and sensory nerve conduction slowing and nerve energy failure that were clearly manifest in the wild-type (PARP(+/+)) diabetic or galactose-fed mice. Two structurally unrelated PARP inhibitors, 3-aminobenzamide and 1,5-isoquinolinediol, reversed established nerve blood flow and conduction deficits and energy failure in streptozotocin-induced diabetic rats. Sciatic nerve immunohistochemistry revealed enhanced poly(ADP-ribosyl)ation in all experimental groups manifesting neuropathic changes. Poly(ADP-ribose) accumulation was localized in both endothelial and Schwann cells. Thus, the current work identifies PARP activation as an important mechanism in diabetic neuropathy and provides the first evidence for the potential therapeutic value of PARP inhibitors in this devastating complication of diabetes.

Animals↗
PubMed2004

[Evaluation of operation and anesthesia on hemodynamic variables in patients undergoing elective abdominal surgery by noninvasive thoracic bioimpedance technique].

OBJECTIVE: To analyse and discuss the effects of elective abdominal operation and anaesthesia on patients' cardiac output via noninvasive thoracic bioimpedance technique. METHODS: Noninvasive monitoring system HeMo-601 was applied to detect the hemodynamic variables of 32 elective abdominal surgery patients. The clinical data of cardiac output (CO), cardiac index (CI), cardiac working per minute (CW), left ventricular end-diastolic pressure (LVEDP), stroke volume (SV), cardiac stroke working (SW) and heart rate (HR) were analysed at 1 hour before operation, 4-6 hours after operation and 24 hours after operation, respectively. RESULTS: No significant differences were found in CO, CI, CW and LVEDP between various time points and preoperation (all P>0.05). SV and SW at 4-6 hours after operation were significant lower than those before operation (all P<0.05). Whereas, SV and SW at 24 hours after operation were no significant differences compared with those before operation (all P>0.05). As compared with preoperation, HR at 4-6 hours after operation was significantly faster (P<0.05). However, there was no significant difference in HR between 24 hours after operation and preoperation (P>0.05). CONCLUSION: The reductions in SV and SW at 4-6 hours after operation might be a result of anaesthesia that could weaken the contraction of heart. The presence of rapidness of HR at 4-6 hours after operation might be a compensatory mechanism for the decreases in SV and SW. Therefore, optimizing adequate infusion by the greatest extent during and after operation is very crucial for the maintenance of CO, CI and tissue perfusion.

Abdomen↗
PubMed2004

[Prediction of food allergy by using cord blood IgE levels].

OBJECTIVE: As more attention is paid to food allergy which is already regarded as a public health problem, there is still a lot of uncertainty as to the mechanisms and there are limited therapeutic methods for this problem. It is of importance to screen the susceptible infants as early as possible. The present study was conducted to learn whether cord blood IgE levels (CBIgE) could be used as a predictor of food allergy, and to find out factors which influence the predictive accuracy of CBIgE. METHODS: The present study enrolled 118 infants born between April 2001and July 2001, and the authors followed up the infants until they were 4 months old. At the end of follow up, 105 infants had complete data for evaluation. Paper radioimmunosorbent tests (PRIST) were used for CBIgE assay, and parents were required to answer the standard questionnaires and the food skin prick tests (SPT) were taken for all infants. RESULTS: At the end of follow-up, the infants were divided into 3 groups based on food allergy status: FA group with obvious food allergy, SFA group with suspected food allergy and NFA group without allergy. The median values of CBIgE levels in FA group were higher than those in SFA and NFA groups (4.80 IU/L, 0.55 IU/L, 0.87 IU/L, P < 0.01). When the cutoff value for CBIgE was set at 0.9 IU/L (CBIgE(0.9)), 42.9% of infants were found to have food allergy in the higher CBIgE group, 6.7% in the lower CBIgE group (P < 0.01, RR 95% CI = 2.715 approximately 15.221); when the cutoff value was set at 0.5 IU/L (CBIgE(0.5)), 30.9% in the higher CBIgE group and 5.00% in the lower CBIgE group (P < 0.01, RR 95% CI = 1.954 approximately 19.552). In addition, the sensitivity of CBIgE(0.9).as a predictor of food allergy, was 78.95% and the specificity, efficiency and odd product were 73.68%, 74.74%, and 10.50, generally better than CBIgE(0.5) of which the sensitivity, specificity, efficiency, odd product were 89.47%, 5.00%, 57.89%, 8.5 (P < 0.01). With the multi-factor stepwise regression analysis, our study indicated that exposure to cigarette smoke (OR 95%CI = 4.3340 approximately 71.2432), animal fur (OR 95% CI = 1.9869 approximately 30.7472), and egg supplement (OR 95% CI = 1.9340 approximately 25.8885) before 4 months of age might be the risk factors which may result in the predictive uncertainty of CBIgE. CONCLUSIONS: Increased CBIgE levels might be the risk factor which result in food allergy; CBIgE(0.9), as a predictor of food allergy, is superior to CBIgE(0.5). However, some environmental factors, such as early exposure to cigarette smoke, animal fur and too early egg supplement would lead to predictive uncertainty of CBIgE.

Female↗
PubMed2004

[Clinical analysis of complications after non- invasive positive pressure ventilation and an inquiry into the respiratory treatment strategy in patients with SARS].

OBJECTIVE: To analyze the clinical data of severe acute respiratory syndrome (SARS) patients with pneumothorax and mediastinal emphysema occurring after the non-invasive positive pressure ventilation (NIPPV), and to inquire into relevant strategy in respiratory treatment in the SARS patients. METHODS: Twenty-seven serious cases of SARS undergone NIPPV were analyzed retrospectively. RESULTS: Pneumothorax and mediastinal emphysema occurred in 7 of 27 serious cases of SARS with NIPPV, and mediastinal emphysema occurred in 1 of 189 cases of SARS without mechanical ventilation (MV). The incidence of pneumothorax and mediastinal emphysema in serious cases of SARS with NIPPV was significantly higher (chi2=25.052, P<0.01) than that in cases of SARS without receiving MV. The peripheral blood oxygen saturation level was not changed significantly after reasonable adjustment of ventilation pressure and increase in oxygen concentration inhaled. Seven cases of pneumothorax and mediastinal emphysema improved gradually. CONCLUSION: The incidence of pneumothorax and mediastinal emphysema in serious SARS patients with NIPPV is significantly higher than that in SARS patients without receiving MV. This might be related to SARS related pulmonary injuries, intensive cough and high mechanical ventilation pressure. The pneumothorax and mediastinal emphysema improve gradually in all cases after reasonable adjustment of mechanical ventilative pressure. So when NIPPV is used in the treatment of serious SARS patients to improve hypoxemia, optimized mechanical ventilative pressure should be acquired in order to avoid pneumothorax and mediastinal emphysema.

Adult↗
PubMed2004

[Study on biological nutrients removal in loop reactor].

The simultaneity nitrification and denitrification (SND) was studied in a loop reactor. In the experiment, the research of biological nutrients removal was carried by changing carbon source and the method of adding carbon source, and the concentration of NOx(-)-N and the dissolved oxygen (DO) level were also inspected. The results indicated that the removal of NH4+-N could be enhanced by adding carbon source with COD 800 mg/L + 800 mg/L. And the concentration of NH4+-N in outlet was lower than 3 mg/L; Lower DO level in the reactor could be made easily by using difficultly reduced carbon source. It was useful to improve the biological nutrients removal. When using ethanol or glycerol as carbon source, the removal efficiency of NH4+-N was better than using glucose.

Ammonia↗
PubMed2003

Studies of electron-transfer and charge-transfer coupling processes at a liquid/liquid interface by double-barrel micropipet technique.

Investigation of a heterogeneous electron-transfer (ET) reaction at the water/1,2-dichloroethane interface employing a double-barrel micropipet technique is reported. The chosen system was the reaction between Fe(CN)63- in the aqueous phase (W) and ferrocene in 1,2-dichloroethane (DCE). According to the generation and the collection currents as well as collection efficiency, the ET-ion-transfer (IT) coupling process at such an interface and competing reactions with the organic supporting electrolyte in the organic phase can be studied. In addition, this technique has been found to be an efficient method to distinguish and measure the charge-transfer coupling reaction between two ions (IT-IT) processes occurring simultaneously at a liquid/liquid interface. On this basis, the formal Gibbs energies of transfer of some ions across the W/DCE interface, such as NO3-, NO2-, Cl-, COO-, TBA+, TPAs+, Cs+, Rb+, K+, Na+, and Li+, for which their direct transfers are usually difficult to obtain because of the IT-IT coupling processes, were quantitatively evaluated.

Journal Article↗
PubMed2003

Studies of effect of phase volume ratio on transfer of ionizable species across the water/ 1,2-dichloroethane interface by a three-electrode setup.

The electrochemical behavior of pyridine distribution at the water/1,2-dichloroethane interface with variable phase volume ratios (r = Vo/Vw) was investigated by cyclic voltammetry. The system was composed of an aqueous droplet supported on a Ag/AgCl disk electrode covered with an organic solution or an organic droplet supported on a Ag/AgTPBCl disk electrode covered with an aqueous solution. In this way, a conventional three-electrode potentiostat can be used to study an ionizable compound transfer process at a liquid/liquid interface with a wide range of phase volume ratios (from 0.0004 to 1 and from 1 to 2500). Using this special cell we designed, only very small volumes of both phase were needed for r equal to unity, which is very useful for the investigation of the distribution of ionizable species at a biphasic system when the available amount of species is limited. The ionic partition diagrams were obtained for different phase volume ratios.

Journal Article↗
PubMed2003

Observation of the marcus inverted region of electron transfer reactions at a liquid/liquid interface.

Scanning electrochemical microscopy was used to probe the influence of a driving force on the heterogeneous electron transfer (ET) processes at the externally polarized water/1,2-dichloroethane interface. Being a part of the driving force, the Galvani potential difference at the interface, Deltaowphi, can be quantitatively controlled in a wide range, allowing the precise measurements of the rate constants of the ET reactions. Two opposite systems were chosen in this work. One was 5,10,15,20-tetraphenyl 21H,23H-porphyrin zinc (ZnPor, O)/Fe(CN)64- (W), and the other was TCNQ (O)/Fe(CN)63- (W). For both systems studied, the relations between the rate constant and the Deltaowphi were of parabolic shape; that is, the rate constants increased initially with the Deltaowphi until reaching a maximum and then decreased steadily as the Deltaowphi increased further. This is in accordance with the prediction of the Marcus theory. To our knowledge, this is the first report that the Marcus inverted region can be observed electrochemically at an unmodified liquid/liquid interface with only one redox couple at each phase. The effect of the concentrations of the organic supporting electrolyte has also been discussed in detail.

Journal Article↗
PubMed2003

Reduction of pentavalent antimony by trypanothione and formation of a binary and ternary complex of antimony(III) and trypanothione.

Several pentavalent antimony compounds have been used for the treatment of leishmaniasis for decades. However, the mechanism of these antimony drugs still remains unclear. One of their targets is thought to be trypanothione, a major low molecular mass thiol inside the parasite. We show that pentavalent antimony (Sb(V)) can be rapidly reduced to its trivalent state by trypanothione at mildly acidic conditions and 310 K ( k=4.42 M(-1) x min(-1) at pH 6.4), and that Sb(III) can be bound to trypanothione to form an Sb(III)-trypanothione complex. NMR data demonstrate that Sb(III) binds to trypanothione at the two thiolates of the cysteine residues, and that the binding is pH dependent and is strongest at biological pH with a stability constant log K=23.6 at 298 K (0.1 M NaNO(3)). The addition of low molecular monothiol ligands such as glutathione and cysteine to the Sb(III)-trypanothione complex results in the formation of a ternary complex. Thiolates from both trypanothione and monothiol bind to the Sb(III) center. The formation of the ternary complex is important, as the antileishmanial properties of the drugs are probably due to a complex between of Sb(III)-trypanothione and enzymes. Although thermodynamically stable, the complex is kinetically labile and the free and bound forms of thiolates exchange on the (1)H NMR timescale. Such a facile exchange may be crucial for the transport of Sb(III) within parasites.

Antimony↗
PubMed2003

Membrane-inserted conformation of transmembrane domain 4 of divalent-metal transporter.

Divalent-metal transporter 1 (DMT1) is involved in the intestinal iron absorption and in iron transport in the transferrin cycle. It transports metal ions at low pH ( approximately 5.5), but not at high pH (7.4), and the transport is a proton-coupled process. Previously it has been shown that transmembrane domain 4 (TM4) is crucial for the function of this protein. Here we provide the first direct experimental evidence for secondary-structural features and membrane insertions of a 24-residue peptide, corresponding to TM4 of DMT1 (DMTI-TM4), in various membrane-mimicking environments by the combined use of CD and NMR spectroscopies. The peptide mainly adopts an alpha-helical structure in trifluoroethanol, SDS and dodecylphosphocholine micelles, and dimyristoyl phosphatidylcholine and dimyristoyl phosphatidylglycerol small unilamellar vesicles. It has been demonstrated from both Halpha secondary shifts and nuclear-Overhauser-enhancement (NOE) connectivities that the peptide is well folded into an alpha-helix from Val(8) to Lys(23) in SDS micelles at pH 4.0, whereas the N-terminus is highly flexible. The alpha-helical content estimated from NMR data is in agreement with that extracted from CD simulations. The highest helicity was observed in the anionic phospholipids [1,2-dimyristoyl- sn -glycero-3-[phospho-rac -(1-glycerol)]], indicating that electrostatic attraction is important for peptide binding and insertion into the membranes. The secondary-structural transition of the peptide occurred at pH 4.3 in the 2,2,2-trifluoroethanol (TFE) water mixed solvent, whereas at a higher pH value (5.6) in SDS micelles, DMT1-TM4 exhibited a more stable structure in SDS micelles than that in TFE in terms of changing the pH and temperature. PAGE did not show high-molecular-mass aggregates in SDS micelles. The position of the peptide relative to SDS micelles was probed by the effects of 5- and 16-doxylstearic acids on the intensities of the peptide proton resonances. The results showed that the majority of the peptide is inserted into the hydrophobic interior of SDS micelles, whereas the C-terminal residues are surface-exposed. The ability of DMT1-TM4 to assume transmembrane features may be crucial for its biological function in vivo.

Amino Acid Sequence↗
PubMed2003

Enhanced production of amyloid precursor protein mRNA by peripheral mononuclear blood cell in Alzheimer's disease.

Previous studies have suggested the involvement of amyloid precursor protein (APP) in Alzheimer's disease (AD), as exons 16 and 17 of the APP gene mutations have been found in some familial AD patients. Furthermore, overexpression and deposition of the beta amyloid peptide, a proteolytic product of APP, have been considered as a pathological hallmark of Alzheimer's disease. Therefore, it is of particular interest to determine the expression of APP gene at the transcription level for better understanding of the roles of APP gene in AD pathogenesis. In this work, we employed the quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) to quantify APP mRNA transcripts in the peripheral mononuclear blood cells (PMBC) of 52 Alzheimer's patients, 28 vascular dementia (VD) patients, and 60 healthy elderly controls. The results showed that the amount (mean +/- SEM) of APP transcripts per microgram of total cDNA was 4.05 +/- 0.27, 2.73 +/- 0.33, and 2.59 +/- 0.27 amole in AD, VD, and healthy controls, respectively. There was a significant increase (P < 0.05) in the expression of APP mRNA transcripts in AD compared with that in VD or in healthy controls. Thus, our data indicated that variation of APP gene expression in PMBC might be a pathogenic source of Alzheimer's disease.

Aged↗
PubMed2003

Three-dimensional localization of divergent region 3 of the ryanodine receptor to the clamp-shaped structures adjacent to the FKBP binding sites.

Of the three divergent regions of ryanodine receptors (RyRs), divergent region 3 (DR3) is the best studied and is believed to be involved in excitation-contraction coupling as well as in channel regulation by Ca(2+) and Mg(2+). To gain insight into the structural basis of DR3 function, we have determined the location of DR3 in the three-dimensional structure of RyR2. We inserted green fluorescent protein (GFP) into the middle of the DR3 region after Thr-1874 in the sequence. HEK293 cells expressing this GFP-RyR2 fusion protein, RyR2(T1874-GFP,) were readily detected by their green fluorescence, indicating proper folding of the inserted GFP. RyR2(T1874-GFP) was further characterized functionally by assays of Ca(2+) release and [(3)H]ryanodine binding. These analyses revealed that RyR2(T1874-GFP) functions as a caffeine- and ryanodine-sensitive Ca(2+) release channel and displays Ca(2+) dependence and [(3)H]ryanodine binding properties similar to those of the wild type RyR2. RyR2(T1874-GFP) was purified from cell lysates in a single step by affinity chromatography using GST-FKBP12.6 as the affinity ligand. The three-dimensional structure of the purified RyR2(T1874-GFP) was then reconstructed using cryoelectron microscopy and single particle image analysis. Comparison of the three-dimensional reconstructions of wild type RyR2 and RyR2(T1874-GFP) revealed the location of the inserted GFP, and hence the DR3 region, in one of the characteristic domains of RyR, domain 9, in the clamp-shaped structure adjacent to the FKBP12 and FKBP12.6 binding sites. COOH-terminal truncation analysis demonstrated that a region between 1815 and 1855 near DR3 is essential for GST-FKBP12.6 binding. These results provide a structural basis for the role of the DR3 region in excitation-contraction coupling and in channel regulation.

Binding Sites↗