Sea foam contains hemoglycin from cosmic dust.

In-falling cosmic dust has left evidence of meteoritic polymer amide in stromatolites, both fossil and modern. In search of evidence for continued present day in-fall, sea foam was collected from two beaches in Rhode Island and subjected to Folch extraction to concentrate amphiphilic components in a chloroform water-methanol interphase layer. Hemoglycin polymer amide molecules previously characterized by MALDI mass spectrometry in meteorites and stromatolites were identified in sea foam either directly, or their fragmentation patterns.

Hemoglycin visible fluorescence induced by x rays.

Hemoglycin, a 1494 Da polymer composed of iron and glycine, has been detected in several carbonaceous meteorites. Iron atoms close out the ends of a 5 nm anti-parallel glycine beta sheet and contribute visible and near infrared absorptions that are not present with glycine alone. The 483 nm absorption of hemoglycin was discovered in theory and then observed on beamline I24 at Diamond Light Source.

Chiral 480 nm absorption in the hemoglycin space polymer: a possible link to replication.

A 1494 Dalton hemoglycin space polymer of Glycine Hydroxy-glycine FeO termed the "core unit" is part of a polymer of Glycine, Si, Fe and O that forms tubes, vesicles and a lattice structure. It has been isolated from four different CV3 meteorites and characterized by mass spectrometry, FIB/SIMS and X-ray analysis. In quantum calculations (HF and DF wB97X-D 6-31G) the polymer has an absorption at 480 nm that is dependent on rectus "R" (= dextro D) chirality in a hydroxy glycine residue whose C-terminus is bonded to an iron atom.

Polymer amide as an early topology.

Hydrophobic polymer amide (HPA) could have been one of the first normal density materials to accrete in space. We present ab initio calculations of the energetics of amino acid polymerization via gas phase collisions. The initial hydrogen-bonded di-peptide is sufficiently stable to proceed in many cases via a transition state into a di-peptide with an associated bound water molecule of condensation.

Entrapment of water by subunit c of ATP synthase.

We consider an ancient protein, and water as a smooth surface, and show that the interaction of the two allows the protein to change its hydrogen bonding to encapsulate the water. This property could have made a three-dimensional microenvironment, 3-4 Gyr ago, for the evolution of subsequent complex water-based chemistry. Proteolipid, subunit c of ATP synthase, when presented with a water surface, changes its hydrogen bonding from an alpha-helix to beta-sheet-like configuration and moves away from its previous association with lipid to interact with water surface molecules.

Topology of the mammalian cell via cryo-FIB etching.

Mapping of a mammalian cell down to a feature size of 20-30 nm in 3D is a goal that will answer many questions concerning the connectivity (topology) of a Eukaryotic cell's traffic routes. These routes are defined and separated from one another by the protein-impregnated lipid membrane barrier of the endoplasmic reticulum (ER). We trace the routes from outside a live flash frozen buccal epithelial cell via gold (Au) labelled pores in the plasma membrane to the ER below and then through the cell as isosurfaces in 3D maps.

Batten disease and the control of the Fo subunit c pore by cGMP and calcium.

Subunit c of ATP synthase functions as a high conductance ion channel, tightly regulated by calcium. We have suggested that the pathogenesis of Batten syndromes involving overaccumulation of subunit c are linked to the protein's ion channel function. In normal electrically excitable tissue the channel could act as a pacer setting nodal voltage via control of cation entry.

Opposing actions of cGMP and calcium on the conductance of the F(0) subunit c pore.

Subunit c of ATP synthase can be purified from neuronal plasma membrane and from the inner mitochondrial membrane. In the latter location the hydrophobic 75 amino acid protein is one component of the F(1) F(0) ATP synthase complex but in the former it is alone as a pore that is capable of generating spontaneous electrical oscillations. Pure mammalian subunit c when reconstituted in lipid bilayers and voltage clamped, yields a voltage sensitive pore that conducts a cation current regulated by calcium.

Biological-to-electronic interface with pores of ATP synthase subunit C in silicon nitride barrier.

An oscillator pore is identified that generates intermittent, large amplitude, ionic current in the plasma membrane. The pore is thought to be composed of 10-12 units of subunit c of ATP synthase. Pore opening and closing is a co-operative process, dependent on the release, or binding, of as many as six calcium ions.

The yeast Saccharomyces cerevisiae does not sequester chloride but can express a functional mammalian chloride channel.

Chloride uptake into yeast was measured as a function of pH. A small amount of uptake was seen at pH values of 3.0 and 4.

Ion pores made of mitochondrial ATP synthase subunit c in the neuronal plasma membrane and Batten disease.

A hypothesis is outlined that the neurodegeneration of the Batten disease syndromes that involve an overaccumulation of subunit c is caused by a newly characterized function of the protein, its ability to assemble in the plasma membrane into ion pores (J. E. M.

A 0.1-700 Hz current through a voltage-clamped pore: candidate protein for initiator of neural oscillations.

A protein of mass 7643 Da and sequence identical to that of subunit c, the pore part, of the mitochondrial adenosine triphosphate synthase complex, was co-purified with cholesterol in crystals formed from a chloroform/methanol extract of bovine brain gray matter plasma membranes. Reconstitution of the protein-containing crystals in phospholipid bilayers and assay of current by patch-clamp analysis, showed an oscillating cation current at constant voltage, typically of frequency 0.5-200 Hz.

Eye CNG channel is modulated by nicotine.

The cyclic-nucleotide gated channel (CNG channel) of the rod outer segment of the retina (ROS) has its closed conformation stabilized by nicotine. Calcium and cGMP influence the Ki of the channel current to nicotine. Calcium lowers the Ki and cGMP increases it, giving a range of Ki between 10(-11) and 10(-8) M.

An insulin-sensitive cation channel controls [Na+]i via [Ca2+]o-regulated Na+ and Ca2+ entry.

The insulin-stimulated cation channel previously identified in patch-clamped muscle preparations is here shown to be responsible for bulk Na+ entry into the cell. The mainly Na+ current of the channel was shown to be accompanied by an inhibitory Ca2+ component responsible for oscillations. Here, using quantitative fluorescence imaging of Fura-2- and SBFI-loaded soleus muscle, we measure changes in [Na+]i and [Ca2+]i related to channel function.

Power spectra and cooperativity of a calcium-regulated cation channel.

In this article we show that a channel complex of cooperatively interacting subunits can produce a power law spectrum with the slope of the spectrum depending on the strength of the cooperative interaction. The effects of cooperativity are explored via a computational model of a calcium-regulated cation channel for which new data is presented. The results, which concern "flickering" conductances, are correlated with prior work on critical fluctuations in the Ising model of ferromagnetism.

An insulin-stimulated cation channel in skeletal muscle. Inhibition by calcium causes oscillation.

A cation channel has been identified in the plasma membrane of skeletal muscle that oscillates open and closed in a regular manner. In an experimental system of patch-clamped reconstituted plasma membrane in phospholipid bilayers, the oscillations are calcium-dependent and constitute regular closing events due to inhibition of the channel by calcium with a Ki of 2.2 +/- 1 x 10(-6) M, followed by reopening.

The alpha-2 isomer of the sodium pump is inhibited by calcium at physiological levels.

The inhibition of the (Na,K)ATPase by calcium was investigated in plasma membrane preparations of rat axolemma, skeletal muscle and kidney outer medulla. Ouabain titration curves demonstrated that physiological calcium (0.08-5 microM) inhibited mainly the high affinity alpha 2 isomer.

Inhibition of active-transport sodium-potassium-A.T.P.ase by myeloma protein.

Patients with multiple myeloma excrete immunoglobulin light chain (Bence-Jones protein) in the urine. Light chain accumulates in the nephron, and this may result in renal disease, which accounts for the death of between 1 in 4 and 1 in 7 patients with multiple myeloma. Myeloma light chain inhibits transport of paraaminohippurate in the kidney.

Polycystic disease of kidney, liver and pancreas; a possible patholgenesis.

5,6,7,8-tetrahydrocarbzzole-3-acetic acid (AH 2835) given to maternal rats throughout their gestation produces an experimental model of the autosomally inherited human infantile polycystic disease Potter type I in the rat foetuses. The affected animals have cystic lesions in their kidneys, liver and pancreas like those seen in the human. Evidence is presented for the aetiology of the experimental lesion being related to the action of AH 2835 on the specific activity of the ouabain sensitive (Na+ + K+)-ATPase of absorptive epithelia.

Enzyme changes in experimental renal microcystic disease.

In an experimental model of human microcystic disease in rats, abnormal changes in tubular enzyme activity were detected as the lesion developed. Decreased activity for alkaline phosphatase, Mg-ATPase, and NaK-ATPase were detected mainly in the proximal tubule, where the lesion was most pronounced. Areas of early fibrosis between the cystic tubules were associated with acid phosphatase activity.