Modularity of membrane-bound charge-translocating protein complexes

2021 ◽  
Author(s):  
Filipa Calisto ◽  
Manuela M. Pereira
Keyword(s):  
Protein Complexes ◽  
Energy Transduction ◽  
Catalytic Subunit ◽  
Electrochemical Potential ◽  
Catalytic Subunits ◽  
Membrane Charge ◽  
Membrane Bound ◽  
Charge Translocation

Energy transduction is the conversion of one form of energy into another; this makes life possible as we know it. Organisms have developed different systems for acquiring energy and storing it in useable forms: the so-called energy currencies. A universal energy currency is the transmembrane difference of electrochemical potential (Δμ~). This results from the translocation of charges across a membrane, powered by exergonic reactions. Different reactions may be coupled to charge-translocation and, in the majority of cases, these reactions are catalyzed by modular enzymes that always include a transmembrane subunit. The modular arrangement of these enzymes allows for different catalytic and charge-translocating modules to be combined. Thus, a transmembrane charge-translocating module can be associated with different catalytic subunits to form an energy-transducing complex. Likewise, the same catalytic subunit may be combined with a different membrane charge-translocating module. In this work, we analyze the modular arrangement of energy-transducing membrane complexes and discuss their different combinations, focusing on the charge-translocating module.

scholarly journals Protein Kinase A Distribution in Meningioma

Cancers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1686 ◽  
Author(s):  
Caretta ◽  
Denaro ◽  
D’Avella ◽  
Mucignat-Caretta
Keyword(s):  
Brain Tissue ◽  
Catalytic Subunit ◽  
Therapeutic Interventions ◽  
Normal Brain ◽  
Local Concentration ◽  
Correlation Pattern ◽  
Catalytic Subunits ◽  
Tissue Specimens ◽  
Pka Catalytic Subunit

Deregulation of intracellular signal transduction pathways is a hallmark of cancer cells, clearly differentiating them from healthy cells. Differential intracellular distribution of the cAMP-dependent protein kinases (PKA) was previously detected in cell cultures and in vivo in glioblastoma and medulloblastoma. Our goal is to extend this observation to meningioma, to explore possible differences among tumors of different origins and prospective outcomes. The distribution of regulatory and catalytic subunits of PKA has been examined in tissue specimens obtained during surgery from meningioma patients. PKA RI subunit appeared more evenly distributed throughout the cytoplasm, but it was clearly detectable only in some tumors. RII was present in discrete spots, presumably at high local concentration; these aggregates could also be visualized under equilibrium binding conditions with fluorescent 8-substituted cAMP analogues, at variance with normal brain tissue and other brain tumors. The PKA catalytic subunit showed exactly overlapping pattern to RII and in fixed sections could be visualized by fluorescent cAMP analogues. Gene expression analysis showed that the PKA catalytic subunit revealed a significant correlation pattern with genes involved in meningioma. Hence, meningioma patients show a distinctive distribution pattern of PKA regulatory and catalytic subunits, different from glioblastoma, medulloblastoma, and healthy brain tissue. These observations raise the possibility of exploiting the PKA intracellular pathway as a diagnostic tool and possible therapeutic interventions.

Membrane-bound energy transduction

Biophysics ◽  
1989 ◽  
pp. 213-228
Author(s):  
Christiaan Sybesma
Keyword(s):  
Energy Transduction ◽  
Membrane Bound

scholarly journals Evolutionary Conservation Levels of Subunits of Histone-Modifying Protein Complexes in Fungi

2009 ◽  
Vol 2009 ◽  
pp. 1-6 ◽  
Author(s):  
Hiromi Nishida
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Histone Acetylation ◽  
Histone Methylation ◽  
Protein Complex ◽  
Histone Acetyltransferase ◽  
Protein Complexes ◽  
Evolutionary Conservation ◽  
Catalytic Subunits ◽  
Evolutionary Lineage ◽  
Conservation Level

Eukaryotes possess a variety of histone-modifying protein complexes. Generally, a histone-modifying protein complex consists of multiple subunits, that is, a catalytic subunit and the associated subunits. In this study, I analyzed 62 and 48 subunits of the histone-modifying protein complexes ofSaccharomyces cerevisiaeandSchizosaccharomyces pombe, respectively. The evolutionary conservation levels of the 110 subunits were measured. The measurements revealed that the conservation levels of the catalytic subunits are significantly higher than those of the associated subunits of the histone acetyltransferase and deacetylase complexes; however, the conservation level of the catalytic subunits is similar to that of the associated subunits of the histone methyltransferase complexes. Thus, in the fungal histone acetylation and deacetylation systems, the catalytic subunits of histone-modifying protein complexes are conserved and the associated subunits are evolutionary lineage-specific. In contrast, in the fungal histone methylation system, both the catalytic and the associated subunits are evolutionary lineage-specific.

An Investigation into Membrane Bound Redox Carriers Involved in Energy Transduction Mechanism in Brevibacterium linens DSM 20158 with Unsequenced Genome

2014 ◽  
Vol 247 (4) ◽  
pp. 345-355
Author(s):  
Khadija Shabbiri ◽  
Catherine H. Botting ◽  
Ahmad Adnan ◽  
Matthew Fuszard ◽  
Shahid Naseem ◽  
...  
Keyword(s):  
Energy Transduction ◽  
Brevibacterium Linens ◽  
Transduction Mechanism ◽  
Membrane Bound

Mechanism of complement cytolysis and the concept of channel-forming proteins

1984 ◽  
Vol 306 (1129) ◽  
pp. 311-324 ◽  
Keyword(s):  
Protein Complexes ◽  
Supramolecular Complexes ◽  
Reaction Sequence ◽  
Native Proteins ◽  
Streptolysin O ◽  
Transmembrane Pores ◽  
Target Cell Membrane ◽  
Membrane Bound ◽  
Self Association ◽  
Protein Channels

Complement damages membranes via the terminal reaction sequence that leads to the formation of membrane-bound, macromolecular C5b-9(m) protein complexes. These complexes represent C5b-8 monomers to which varying numbers of C9 molecules can be bound. Complexes carrying high numbers of C9 ( ca . 6/8-12/16?) exhibit the morphology of hollow protein channels. Because they are embedded within the lipid bilayer, aqueous transmembrane pores are generated that represent the primary lesions caused by complement in the target cell membrane. Many other proteins damage membranes by forming channels in a manner analogous to the C5b-9(m) complex. Two prototypes of bacterial exotoxins, Staphylococcus aureus α-toxin and streptolysin-O, are discussed in this context, and attention is drawn to the numerous analogies existing among these protein systems. Common to all is the process of self-association of the native proteins to form supramolecular complexes. This event is in turn accompanied by a unique transition of the molecules from a hydrophilic to an amphiphilic state.

Evolution of the soluble nitrate reductase: defining the monomeric periplasmic nitrate reductase subgroup

2006 ◽  
Vol 34 (1) ◽  
pp. 122-126 ◽  
Author(s):  
B.J.N. Jepson ◽  
A. Marietou ◽  
S. Mohan ◽  
J.A. Cole ◽  
C.S. Butler ◽  
...  
Keyword(s):  
Nitrate Reductase ◽  
Structural Alignment ◽  
Bioinformatic Analysis ◽  
Catalytic Subunit ◽  
Surface Polarity ◽  
Redox Partner ◽  
Redox Partners ◽  
Membrane Bound ◽  
And Function ◽  
Nitrate Reductases

Bacterial nitrate reductases can be classified into at least three groups according to their localization and function, namely membrane-bound (NAR) or periplasmic (NAP) respiratory and cytoplasmic assimilatory (NAS) enzymes. Monomeric NASs are the simplest of the soluble nitrate reductases, although heterodimeric NASs exist, and a common structural arrangement of NAP is that of a NapAB heterodimer. Using bioinformatic analysis of published genomes, we have identified more representatives of a monomeric class of NAP, which is the evolutionary link between the monomeric NASs and the heterodimeric NAPs. This has further established the monomeric structural clade of NAP. The operons of the monomeric NAP do not contain NapB and suggest that other redox partners are employed by these enzymes, including NapM or NapG predicted proteins. A structural alignment and comparison of the monomeric and heterodimeric NAPs suggests that a difference in surface polarity is related to the interaction of the respective catalytic subunit and redox partner.

Sign in / Sign up

Export Citation Format

Share Document