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The cell without a pumping membrane

Some accounts of the cell place the weight on the state of its proteins and cytoplasm. In the held texts, Nasonov's school argued that excitation and damage are stages of protein denaturation13. A later review of alkaliphilic bacteria keeps the proton pumps and asks why pumped protons do not mix at once with the bulk phase56.

Earliest held
2010, Matveev VV
Most discussed in
Native aggregation as a cause of origin of…, 2010
In the library
15 passages in 2 works
Rewritten
2026-10-03
18501875190019251950197520002025Matveev VV, 20101Matveev VV, 20102Matveev VV, 20103Matveev VV, 20104Preiss L, Hicks DB, Suzuki S, Meier T…, 20155Preiss L, Hicks DB, Suzuki S, Meier T…, 20156Preiss L, Hicks DB, Suzuki S, Meier T…, 20157Preiss L, Hicks DB, Suzuki S, Meier T…, 20158Preiss L, Hicks DB, Suzuki S, Meier T…, 20159
01

Nasonov and denaturation

Matveev (2010) reports that Nasonov traced the changes in cytoplasm during the nonspecific reaction to stages of cell protein denaturation. The reason given was that isolated proteins change in very similar ways when they are denatured1. The result was the denaturational theory of cell excitation and damage. Matveev adds that the structural meaning of denaturation was unclear in Nasonov's time. He gives the present assumption that denaturation is the destruction of the tertiary and secondary structure of a protein2. The theory therefore covers two things, excitation and damage, with one cause.

02

Excitation shades into damage

As Matveev describes the theory, the first denaturational changes are still reversible. They underlie cell excitation, and the examples listed are activation of secretory function, muscle contraction and the action potential3. Deeper protein changes disturb normal cell function but may still be reversible. With further damage the changes become irreversible and the cell dies4. The theory thus places excitation, injury and death on one series of protein changes that differ in depth.

03

Protons and the bulk phase

Preiss and co-authors (2015) review a different problem in alkaliphilic bacteria. The bulk proton motive force seemed too small to account for the ATP synthesis observed. Much of the effort then went to explaining rapid movement of protons from the pumping complexes to the ATP synthase5. The proposals include near-membrane barriers to proton equilibration with the bulk phase, such as compartmentalization and proton electrostatics. All of them focus on the near-membrane environment6. The membrane remains the site of pumping in this work.

04

Lipids and outer membranes

Preiss and co-authors also raise the outer membrane of Gram-negative alkaliphiles as a possible delay to proton equilibration. They suggest the outer membrane of mitochondria may play some role too7. Another suggestion is that the high cardiolipin level of B. pseudofirmus OF4 might delay equilibration8. The authors note that in that species, mutants lacking detectable cardiolipin were not impaired in non-fermentative growth at high pH9. The passage does not settle which barrier matters.

SourcesEach quotation was checked word for word against the passage it opens.
  1. Nasonov called the cause of these changes the stages of cell protein denaturation, as the changes of properties of isolated proteins during denaturation are very similar to the changes in the cytoplasm during the nonspecific reaction.Matveev VV, 2010 · Native aggregation as a cause of origin of temporary cellular structures needed… · open at passage 6
  2. The structural changes of protein denaturation were unclear in Nasonov's time. Nowadays, it is assumed that the denaturation is the destruction of the tertiary and secondary structure of a protein.Matveev VV, 2010 · Native aggregation as a cause of origin of temporary cellular structures needed… · open at passage 6
  3. According to this theory, the initial stages of denaturational changes, when they still are reversible, underlie cell excitation (activation of secretory function, muscle contraction, action potential, etc.).Matveev VV, 2010 · Native aggregation as a cause of origin of temporary cellular structures needed… · open at passage 26
  4. More profound protein changes lead to disturbances of normal cell functioning, but may still be reversible. Then, with further development of damage, denaturational changes become irreversible and the cell dies.Matveev VV, 2010 · Native aggregation as a cause of origin of temporary cellular structures needed… · open at passage 26
  5. Much of the effort and hypotheses have focused on rapid movement of protons from the proton-pumping complexes to the proton-coupled ATP synthase.Preiss L, Hicks DB, Suzuki S, Meier T, Krulwich TA, 2015 · Alkaliphilic Bacteria with Impact on Industrial Applications, Concepts of Early… · open at passage 30
  6. Proposals of near-membrane barriers to proton equilibration with the bulk phase include compartmentalization and aspects of proton-electrostaticsPreiss L, Hicks DB, Suzuki S, Meier T, Krulwich TA, 2015 · Alkaliphilic Bacteria with Impact on Industrial Applications, Concepts of Early… · open at passage 30
  7. perhaps the outer membrane of mitochondria should be considered for playing at least some role in delaying pumped proton equilibration with the bulk phase or cytoplasmPreiss L, Hicks DB, Suzuki S, Meier T, Krulwich TA, 2015 · Alkaliphilic Bacteria with Impact on Industrial Applications, Concepts of Early… · open at passage 32
  8. It has been suggested that particular phospholipids might play a role, and specifically the high cardiolipin level of B. pseudofirmus OF4 might delay proton equilibrationPreiss L, Hicks DB, Suzuki S, Meier T, Krulwich TA, 2015 · Alkaliphilic Bacteria with Impact on Industrial Applications, Concepts of Early… · open at passage 32
  9. mutants lacking detectable cardiolipin were not impaired in non-fermentative growth at high pHPreiss L, Hicks DB, Suzuki S, Meier T, Krulwich TA, 2015 · Alkaliphilic Bacteria with Impact on Industrial Applications, Concepts of Early… · open at passage 32
Linked ideas
Chemiosmosis rests on a membrane proton gradient. The alkaliphile review asks why pumped protons stay near the membrane instead of equilibrating with the bulk phase.
The alkaliphile ATP synthase puzzle concerns how pumped protons reach the synthase and drive ATP synthesis.
Preiss and co-authors suggest the mitochondrial outer membrane may delay pumped proton equilibration with the cytoplasm.
Nasonov's school tied excitation to protein change in the cytoplasm. Membrane-based accounts place the electrical event at the membrane.
The action potential is one of the excitation events that Nasonov's theory attributes to early, reversible protein denaturation.
Excitation in the denaturational theory includes the action potential, which is the electrical event that depolarization describes.
Where it is discussedPassages matching association-induction, sorption theory, Nasonov, Troshin
2010Native aggregation as a cause of origin of temporary cellular structures needed… · Matveev VV13
2015Alkaliphilic Bacteria with Impact on Industrial Applications, Concepts of Early… · Preiss L, Hicks DB, Suzuki S, Meier T…2