Alligator haemoglobin in carbonmonoxy form
Ontology highlight
ABSTRACT:
SUBMITTER: Tomohiro Nishizawa
PROVIDER: EMPIAR-11988 | biostudies-other |
REPOSITORIES: biostudies-other
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| EMPIAR-11989 | biostudies-other
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| EMPIAR-11990 | biostudies-other
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| EMPIAR-11991 | biostudies-other
Project description:The solution structure of human adult carbonmonoxy hemoglobin (HbCO A) was refined using stereospecifically assigned methyl groups and residual dipolar couplings based on our previous nuclear magnetic resonance structure. The tertiary structures of individual chains were found to be very similar to the X-ray structures, while the quaternary structures in solution at low salt concentrations resembled the X-ray R structure more than the R2 structure. On the basis of chemical shift perturbation by inositol hexaphosphate (IHP) titration and docking, we identified five possible IHP binding sites in HbCO A. Amide-water proton exchange experiments demonstrated that ?Thr38 located in the ?1?2 interface and several loop regions in both ?- and ?-chains were dynamic on the subsecond time scale. Side chain methyl dynamics revealed that methyl groups in the ?1?2 interface were dynamic, but those in the ?1?1 interface were quite rigid on the nanosecond to picosecond and millisecond to microsecond time scales. All the data strongly suggest a dynamic ?1?2 interface that allows conformational changes among different forms (like T, R, and R2) easily in solution. Binding of IHP to HbCO A induced small structural and dynamic changes in the ?1?2 interface and the regions around the hemes but did not increase the conformational entropy of HbCO A. The binding also caused conformational changes on the millisecond time scale, very likely arising from the relative motion of the ?1?1 dimer with respect to the ?2?2 dimer. Heterotropic effectors like IHP may change the oxygen affinity of Hb through modulating the relative motion of the two dimers and then further altering the structure of heme binding regions.
| S-EPMC4013309 | biostudies-literature
Project description:Cationic antimicrobial peptides and their therapeutic potential have garnered growing interest because of the proliferation of bacterial resistance. However, the discovery of new antimicrobial peptides from animals has proven challenging due to the limitations associated with conventional biochemical purification and difficulties in predicting active peptides from genomic sequences, if known. As an example, no antimicrobial peptides have been identified from the American alligator, Alligator mississippiensis, although their serum is antimicrobial. We have developed a novel approach for the discovery of new antimicrobial peptides from these animals, one that capitalizes on their fundamental and conserved physico-chemical properties. This sample-agnostic process employs custom-made functionalized hydrogel microparticles to harvest cationic peptides from biological samples, followed by de novo sequencing of captured peptides, eliminating the need to isolate individual peptides. After evaluation of the peptide sequences using a combination of rational and web-based bioinformatic analyses, forty-five potential antimicrobial peptides were identified, and eight of these peptides were selected to be chemically synthesized and evaluated. The successful identification of multiple novel peptides, exhibiting antibacterial properties, from Alligator mississippiensis plasma demonstrates the potential of this innovative discovery process in identifying potential new host defense peptides.
| S-EPMC4324634 | biostudies-literature
Project description:The muscles that effect lung ventilation are key to understanding the evolutionary constraints on animal form and function. Here, through electromyography, we demonstrate a newly discovered respiratory function for the iliocostalis muscle in the American alligator ( Alligator mississippiensis). The iliocostalis is active during expiration when breathing on land at 28°C and this activity is mediated through the uncinate processes on the vertebral ribs. There was also an increase in muscle activity during the forced expirations of alarm distress vocalizations. Interestingly, we did not find any respiratory activity in the iliocostalis when the alligators were breathing with their body submerged in water at 18°C, which resulted in a reduced breathing frequency. The iliocostalis is an accessory breathing muscle that alligators are able to recruit in to assist expiration under certain conditions.
| S-EPMC6684976 | biostudies-literature
Project description:Gene expression in alligator scales
2019-06-17 | GSE115975 | GEO
Project description:The oxygen transport system in mammals is extensively remodelled in response to repeated bouts of activity, but many reptiles appear to be 'metabolically inflexible' in response to exercise training. A recent report showed that estuarine crocodiles (Crocodylus porosus) increase their maximum metabolic rate in response to exhaustive treadmill training, and in the present study, we confirm this response in another crocodilian, American alligator (Alligator mississippiensis). We further specify the nature of the crocodilian training response by analysing effects of training on aerobic [citrate synthase (CS)] and anaerobic [lactate dehydrogenase (LDH)] enzyme activities in selected skeletal muscles, ventricular and skeletal muscle masses and haematocrit. Compared to sedentary control animals, alligators regularly trained for 15 months on a treadmill (run group) or in a flume (swim group) exhibited peak oxygen consumption rates higher by 27 and 16%, respectively. Run and swim exercise training significantly increased ventricular mass (~11%) and haematocrit (~11%), but not the mass of skeletal muscles. However, exercise training did not alter CS or LDH activities of skeletal muscles. Similar to mammals, alligators respond to exercise training by increasing convective oxygen transport mechanisms, specifically heart size (potentially greater stroke volume) and haematocrit (increased oxygen carrying-capacity of the blood). Unlike mammals, but similar to squamate reptiles, alligators do not also increase citrate synthase activity of the skeletal muscles in response to exercise.
| S-EPMC2768110 | biostudies-other