Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:Q86TM3 (cage)
 29,987 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ultrafast absorption spectroscopy is used to study heme-NO recombination at room temperature in aqueous buffer on time scales where the ligand cannot leave its cage environment. While a single barrier is observed for the cage recombination of NO with heme in the absence of globin, recombination in hemoglobin and myoglobin is nonexponential. Examination of hemoglobin with and without inositol hexaphosphate points to proximal constraints as important determinants of the geminate rebinding kinetics. Molecular dynamics simulations of myoglobin and heme-imidazole subsequent to ligand dissociation were used to investigate the transient behavior of the Fe-proximal histidine coordinate and its possible involvement in geminate recombination. The calculations, in the context of the absorption measurements, are used to formulate a distinction between nonexponential rebinding that results from multiple protein conformations (substates) present at equilibrium or from nonequilibrium relaxation of the protein triggered by a perturbation such as ligand dissociation. The importance of these two processes is expected to depend on the time scale of rebinding relative to equilibrium fluctuations and nonequilibrium relaxation. Since NO rebinding occurs on the picosecond time scale of the calculated myoglobin relaxation, a time-dependent barrier is likely to be an important factor in the observed nonexponential kinetics. The general implications of the present results for ligand binding in heme proteins and its time and temperature dependence are discussed. It appears likely that, at low temperatures, inhomogeneous protein populations play an important role and that as the temperature is raised, relaxation effects become significant as well.
 ...
PMID:Ligand binding and protein relaxation in heme proteins: a room temperature analysis of NO geminate recombination. 201 66

It has been shown that malignant activation of ras proto-oncogenes was mediated by point mutations which resulted in the single amino acid conversions at positions 12, 13 or 61 of the ras gene products (p21 proteins). By analyzing randomly mutated ras genes, it has been demonstrated that amino acid substitutions at residues 12, 13, 59 and 63 activated p21. Furthermore, it has been shown that residues 16, 116 and 119 in p21 played critical roles in the guanine nucleotide binding and, consequently, the ability of the protein to induce changes characteristic of cellular transformation. By using the protein conformational prediction method of Chou and Fasman, the present work predicts that these critical amino acids, except glutamic acid at position 63, are located within beta-turns. The major "hot spots" for ras activation are codons 12 and 61. The author has predicted in an earlier paper that the single amino acid conversions at positions 12 and 61 would occur at beta-turn conformation consisting of residues 10-13 and 58-61, respectively. In the present study, probabilities of beta-turn occurrence at residues 10-13 or 58-61 of the p21 proteins encoded by various ras genes are compared. The probability for the normal p21 containing glycine as residue 12 is greatest, and the cancer-associated variants show less probabilities. The single amino acid substitutions at position 61 do not cause so decreased probabilities of beta-turn potential at residues 58-61, except the replacement by histidine. Histidine at position 61 is not predicted as occurring within a beta-turn.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Critical amino acids of p21 protein are located within beta-turns: further evaluation. 332 19

Prosthetic valve infective endocarditis was found in 31 out of 275 autopsies on patients with valvular prostheses. Mean postoperative survival was 332 days. Thirty patients had mechanical valves and only 1 had an infected tissue valve. The commonest pathogens were staphylococci, followed by Gram-negative bacilli and fungi. In all the patients with mechanical valves the infection was situated at the host-prosthesis sewing ring interface, and most also had vegetations on the prosthetic struts or cage. The infected tissue valve had vegetations on the prosthetic cusps only. Ring abscesses were present in one-third of cases and had destroyed the bundle of His in 1 patient. Clinically recognized pre-operative infective endocarditis was present in only 3 out of the 31 patients. Seven of the 31 patients died because of malfunction of the prosthesis, 10 died of systemic embolism, 4 of ruptured mycotic aneurysms, and the remaining 10 of other causes including myocardial failure, pyaemic abscesses and toxaemia.
 ...
PMID:Prosthetic valve endocarditis. A clinicopathological study of 31 cases. 396 36

Intraperitoneally administered morphine induced catalepsy in mice. Morphine pretreatment however, failed to antagonize apomorphine-induced cage climbing behaviour thereby ruling out the possibility of its possessing DA receptor blocking activity. Pretreatment with L-histidine, a precursor of histamine, and atropine, potentiated the cataleptic effect of morphine whilst pretreatment with chlorcyclizine, an H1 receptor blocker, and naloxone, a morphine antagonist, antagonized morphine-catalepsy. Pretreatment with metiamide, an H2 receptor blocker, and methysergide, a 5-HT antagonist, did not significantly alter the cataleptic effect of morphine. The results with L-histidine and chlorcyclizine suggest an involvement of central histaminergic mechanisms in the cataleptogenic effect of morphine in mice. Further, as the cataleptic effect of morphine was also antagonized by naloxone it appears that the interaction of morphine with the central histaminergic mechanisms is mediated through specific opiate receptors.
 ...
PMID:Involvement of histaminergic mechanisms in the cataleptogenic effect of morphine in mice. 612 Oct 29

We present a case of severe breathing abnormality during sleep in a young man who had had poliomyelitis 20 yr before. His sleep disorder led to respiratory failure and cor pulmonale, which were greatly improved by oxygen therapy. A study of this case and those previously described supports the notion that brainstem damage during acute poliomyelitis is important in the later appearance of sleep-disordered breathing. In addition, such patients usually have mechanical abnormalities involving the thoracic cage and respiratory muscles. These ventilatory restrictions amplify the pathophysiologic effects of abnormal central nervous system control of breathing during sleep, and we suggest that their presence has a key role in the development of sleep apnea syndrome in these patients.
 ...
PMID:Sleep apnea syndrome after poliomyelitis. 684 37

A new ECG-amplifier system for recording cardiac microvolt potentials from the body surface is described. The improvement in signal-to-noise ratio was achieved by using specially designed suction electrodes, which were isolated from each other; by applying parallel signal averaging from four electrode pairs via four low-noise amplifiers; and by conducting the registration in Faraday cage. in 14 normal subjects, 12 patients with coronary heart disease and one patient with surgically corrected ventricular septal defect and pulmonary stenosis, pre-P-potentials (possible sinus node activity), His bundle potentials and ventricular late potentials were recorded with differing degrees of success. Variations of the time intervals to the preceding QRS complex were observed within the S-T segment in six of nine patients with demonstrable ventricular late ventricular late potentials. The advantage of such continuously recording ECG system lies in the highly accurate registration of cardiac micropotentials, particularly with ventricular late potentials that are changing in time, whereas the signal-averaging technique does not provide such possibilities.
 ...
PMID:[Continuous registration of micropotentials of the human heart. Initial experiences with a new high resolution ECG amplifier system]. 717 58

Recoverin is a member of the EF-hand family of calcium-binding proteins involved in the transduction of light by vertebrate photoreceptors. Recoverin also was identified as an autoantigen in the degenerative disease of the retina known as cancer-associated retinopathy (CAR), a paraneoplastic syndrome whereby immunological events lead to the degeneration of photoreceptors in some individuals with cancer. In this study, we demonstrate that recoverin is expressed in the lung tumor of a CAR patient but not in similar tumors obtained from individuals without the associated retinopathy. Recoverin was identified intially by Western blot analysis of the CAR patient's biopsy tissue by using anti-recoverin antibodies generated against different regions of the recoverin molecule. In addition, cultured cells from the biopsy tissue expressed recoverin, as demonstrated by reverse transcription-PCR using RNA extracted from the cells. The immunodominant region of recoverin also was determined in this study by a solid-phase immunoassay employing overlapping heptapeptides encompassing the entire recoverin sequence. Two linear stretches of amino acids (residues 64-70, Lys-Ala-Tyr-Ala-Gln-His-Val; and 48-52, Gln-Phe-Gln-Ser-Ile) made up the major determinants. One of the same regions of the recoverin molecule (residues 64-70) also was uniquely immunopathogenic, causing photoreceptor degeneration upon immunization of Lewis rats with the corresponding peptide. These data demonstrate that the neural antigen recoverin more than likely is responsible for the immunological events associated with vision loss in some patients with cancer. These data also establish CAR as one of the few autoimmune-mediated diseases for which the specific self-antigen is known.
 ...
PMID:Recoverin, a photoreceptor-specific calcium-binding protein, is expressed by the tumor of a patient with cancer-associated retinopathy. 756 96

Galen (129-200 AD) produced a large written output which was to remain one of the major basis of clinical medicine for centuries. His contribution to respiration, reported in his own books and in those of Oribasius, was that of a chest physician and of an experimental physiologist. He described in minute details how to perform a remarkable series of experiments by which he demonstrated the anatomy and function of the respiratory muscles. He described the actions of the diaphragm and how it moves the rib cage, in a series of spinal chord sections and muscle denervations. He investigated the passive or active nature of expiration and made fine observations of lung movements through the exposed pleural space. He described the interaction between the lungs and chest wall and developed the concept of interaction between ribcage and abdominal muscles in maintaining the position of the diaphragm, showing a clear understanding of the principle that the diaphragm can move upward during an isovolume manoeuvre as long as the ribcage is allowed to expand. A skillful clinician, Galen applied his theories of the analysis of problems at the bedside, particularly in patients affected with dyspnoea which he attributed to respiratory muscle dysfunction.
 ...
PMID:History of diaphragm physiology: the achievements of Galen. 774 82

Oxidation of NADH by decavanadate, a polymeric form vanadate with a cage-like structure, in presence of rat liver microsomes followed a biphasic pattern. An initial slow phase involved a small rate of oxygen uptake and reduction of 3 of the 10 vanadium atoms. This was followed by a second rapid phase in which the rates of NADH oxidation and oxygen uptake increased several-fold with a stoichiometry of NADH: O2 of 1:1. The burst of NADH oxidation and oxygen uptake which occurs in phosphate, but not in Tris buffer, was prevented by SOD, catalase, histidine, EDTA, MnCl2 and CuSO4, but not by the hydroxyl radical quenchers, ethanol, methanol, formate and mannitol. The burst reaction is of a novel type that requires the polymeric structure of decavanadate for reduction of vanadium which, in presence of traces of H2O2, provides a reactive intermediate that promotes transfer of electrons from NADH to oxygen.
 ...
PMID:A novel phenomenon of burst of oxygen uptake during decavanadate-dependent oxidation of NADH. 851 Jun 71

We have developed a system for analysis of histidine-tagged (His-tagged) retrovirus core (Gag) proteins, assembled in vitro on lipid monolayers consisting of egg phosphatidylcholine (PC) plus the novel lipid DHGN. DHGN was shown to chelate nickel by atomic absorption spectrometry, and DHGN-containing monolayers specifically bound gold conjugates of His-tagged proteins. Using PC + DHGN monolayers, we examined membrane-bound arrays of an N-terminal His-tagged Moloney murine leukemia virus (M-MuLV) capsid (CA) protein, His-MoCA, and in vivo studies suggest that in vitro-derived His-MoCA arrays reflect some of the Gag protein interactions which occur in assembling virus particles. The His-MoCA proteins formed extensive two-dimensional (2D) protein crystals, with reflections out to 9.5 A resolution. The image-analyzed 2D projection of His-MoCA arrays revealed a distinct cage-like network. The asymmetry of the individual building blocks of the network led to the formation of two types of hexamer rings, surrounding protein-free cage holes. These results predict that Gag hexamers constitute a retrovirus core substructure, and that cage hole sizes define an exclusion limit for entry of retrovirus envelope proteins, or other plasma membrane proteins, into virus particles. We believe that the 2D crystallization method will permit the detailed analysis of retroviral Gag proteins and other His-tagged proteins.
 ...
PMID:Structural analysis of membrane-bound retrovirus capsid proteins. 913 37


1 2 3 4 5 6 7 8 9 10 Next >>