scholarly journals Regulation and Functional Complexity of the Chlorophyll-Binding Protein IsiA

2021 ◽  
Vol 12 ◽  
Author(s):  
Anqi Jia ◽  
Yanli Zheng ◽  
Hui Chen ◽  
Qiang Wang
Keyword(s):  
Iron Deficiency ◽  
Binding Protein ◽  
Protein A ◽  
Laboratory Research ◽  
Ferric Ions ◽  
Ferrous Ions ◽  
Photosynthetic Organisms ◽  
Iron Deficient ◽  
Complex Regulation ◽  
Pigment Protein Complex

As the oldest known lineage of oxygen-releasing photosynthetic organisms, cyanobacteria play the key roles in helping shaping the ecology of Earth. Iron is an ideal transition metal for redox reactions in biological systems. Cyanobacteria frequently encounter iron deficiency due to the environmental oxidation of ferrous ions to ferric ions, which are highly insoluble at physiological pH. A series of responses, including architectural changes to the photosynthetic membranes, allow cyanobacteria to withstand this condition and maintain photosynthesis. Iron-stress-induced protein A (IsiA) is homologous to the cyanobacterial chlorophyll (Chl)-binding protein, photosystem II core antenna protein CP43. IsiA is the major Chl-containing protein in iron-starved cyanobacteria, binding up to 50% of the Chl in these cells, and this Chl can be released from IsiA for the reconstruction of photosystems during the recovery from iron limitation. The pigment–protein complex (CPVI-4) encoded by isiA was identified and found to be expressed under iron-deficient conditions nearly 30years ago. However, its precise function is unknown, partially due to its complex regulation; isiA expression is induced by various types of stresses and abnormal physiological states besides iron deficiency. Furthermore, IsiA forms a range of complexes that perform different functions. In this article, we describe progress in understanding the regulation and functions of IsiA based on laboratory research using model cyanobacteria.

The role of lactoferrin binding protein B in mediating protection against human lactoferricin1This article is part of a Special Issue entitled Lactoferrin and has undergone the Journal's usual peer review process.

2012 ◽  
Vol 90 (3) ◽  
pp. 417-423 ◽  
Author(s):  
Ari Morgenthau ◽  
Margaret Livingstone ◽  
Paul Adamiak ◽  
Anthony B. Schryvers
Keyword(s):  
Peer Review Process ◽  
Binding Protein ◽  
Iron Acquisition ◽  
Protein A ◽  
Human Lactoferrin ◽  
Cationic Antimicrobial Peptide ◽  
Iron Source ◽  
Iron Deficient ◽  
Protein B

Bacteria that inhabit the mucosal surfaces of the respiratory and genitourinary tracts of mammals encounter an iron-deficient environment because of iron sequestration by the host iron-binding proteins transferrin and lactoferrin. Lactoferrin is also present in high concentrations at sites of inflammation where the cationic, antimicrobial peptide lactoferricin is produced by proteolysis of lactoferrin. Several Gram-negative pathogens express a lactoferrin receptor that enables the bacteria to use lactoferrin as an iron source. The receptor is composed of an integral membrane protein, lactoferrin binding protein A (LbpA), and a membrane-bound lipoprotein, lactoferrin binding protein B (LbpB). LbpA is essential for growth with lactoferrin as the sole iron source, whereas the role of LbpB in iron acquisition is not yet known. In this study, we demonstrate that LbpB from 2 different species is capable of providing protection against the killing activity of a human lactoferrin-derived peptide. We investigated the prevalence of lactoferrin receptors in bacteria and examined their sequence diversity. We propose that the protection against the cationic antimicrobial human lactoferrin-derived peptide is associated with clusters of negatively charged amino acids in the C-terminal lobe of LbpB that is a common feature of this protein.

Binding of Human Platelet Glycoprotein lb and Actin to Fragments of Actin-Binding Protein

1992 ◽  
Vol 67 (02) ◽  
pp. 252-257 ◽  
Author(s):  
Anne M Aakhus ◽  
J Michael Wilkinson ◽  
Nils Olav Solum
Keyword(s):  
Actin Filaments ◽  
High Speed ◽  
Binding Protein ◽  
Protein A ◽  
Actin Binding ◽  
Platelet Glycoprotein ◽  
Actin Binding Protein ◽  
Crossed Immunoelectrophoresis ◽  
Triton X ◽  
Calpain Inhibitors

SummaryActin-binding protein (ABP) is degraded into fragments of 190 and 90 kDa by calpain. A monoclonal antibody (MAb TI10) against the 90 kDa fragment of ABP coprecipitated with the glycoprotein lb (GP lb) peak observed on crossed immunoelectrophoresis of Triton X-100 extracts of platelets prepared without calpain inhibitors. MAb PM6/317 against the 190 kDa fragment was not coprecipitated with the GP lb peak under such conditions. The 90 kDa fragment was adsorbed on protein A agarose from extracts that had been preincubated with antibodies to GP lb. This supports the idea that the GP Ib-ABP interaction resides in the 90 kDa region of ABP. GP lb was sedimented with the Triton-insoluble actin filaments in trace amounts only, and only after high speed centrifugation (100,000 × g, 3 h). Both the 190 kDa and the 90 kDa fragments of ABP were sedimented with the Triton-insoluble actin filaments.

scholarly journals AB1240 C4B BINDING PROTEIN AND WARFARIN IN THE ANTIPHOSPHOLIPID SYNDROME

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 1911.2-1911
Author(s):  
G. Grosso ◽  
K. Sandholm ◽  
I. Gunnarsson ◽  
A. Zickert ◽  
A. Vikerfors ◽  
...  
Keyword(s):  
Antiphospholipid Syndrome ◽  
Mediation Analysis ◽  
Binding Protein ◽  
Protein A ◽  
Protein S ◽  
Protein Isoforms ◽  
Type I ◽  
Complement Inhibitor ◽  
Warfarin Treatment ◽  
The Impact

Background:Complement plays a role in the Antiphospholipid Syndrome (APS). C4b Binding Protein (C4BP) is a complement inhibitor with anticoagulant function (1). It belongs to the same protein family as β2GPI, the main antigen in APS. Its main isoform is bound to protein S in the circulation. Levels of both protein S and C4BP are known to be reduced by warfarin treatment (2) as well as by aPL, directly and indirectly.Objectives:To investigate the levels of C4BP in primary (p) and secondary (s) APS, also considering warfarin treatment.Methods:The total amount of C4BP (C4BPt) was measured by using magnetic carboxylated microspheres which were coupled with a monoclonal antibody against the α-chain of human-C4BP to capture the antigen. To detect C4BPt the same antibody was used, biotinylated. The binding of biotinylated antibodies was detected by streptavidin-phycoerythrin and data were collected using a MAGPIX Multiplex Reader. Using independent t-test, we compared C4BP in 118 SLE patients with repeated positivity for Antiphospholipid antibodies (aPL) (39/118 on warfarin), 291 aPL negative SLE patients (16/291 on warfarin), 67 pAPS (33/67 on warfarin), and 322 controls (none on warfarin). We then performed an interaction and a mediation analysis (3) in the SLE group to study the impact of warfarin on C4BP levels: since warfarin is mostly prescribed to aPL+ patients, it is considered a mediator in the reducing effect of aPL on C4BP. Therefore we compared individuals exposed and non-exposed to the presence of aPL with or without the mediator warfarin and calculated the percentage of reduction in C4BP that could be attributed to aPL or warfarin.Results:Overall C4BP is 20% reduced in aPL+ patients (fig 1), independently of SLE, past thrombotic events and nephritis. Warfarin treated patients have lower levels of C4BP (fig 2). According to mediation analysis 11% of C4BP reduction is due to aPL and 9% to warfarin.Figure 1.C4BP in different subgroups (67 pAPS, 118 SLEaPL+, 291 SLEaPL-, 322 controls)Figure 2.C4BP in 67 pAPS patients, 33/67 on warfarinConclusion:Both aPL and warfarin decrease levels of C4BP, a complement and coagulation regulator. Reduction of this complement inhibitor could contribute to complement activation and thrombosis in APS. Our results raise new questions regarding the effects of warfarin treatment on complement and coagulation in APS.References:[1]Dahlbäck B. C4b-binding protein: a forgotten factor in thrombosis and hemostasis. Seminars in thrombosis and hemostasis 2011; 37(4): 355.[2]Zöller B, García de Frutos P, Dahlbäck B. Evaluation of the relationship between protein S and C4b-binding protein isoforms in hereditary protein S deficiency demonstrating type I and type III deficiencies to be phenotypic variants of the same genetic disease. Blood 1995; 85(12): 3524.[3]Vanderweele TJ, Vansteelandt S. Conceptual issues concerning mediation, interventions and composition. Statistics and Its Interface 2009; 2(4): 457-68.Disclaimer:AV is employed at the Swedish Medical Products Agency, the views expressed in this paper are the personal views of the authors and not necessarily the views of the Governement AgencyAcknowledgments:Thanks to the Biostatistics Core Facility, Karolinska UniversityDisclosure of Interests:None declared

Factors associated with longitudinal changes in serum concentrations of Mac-2 binding protein: A prospective 3-year observational study

2019 ◽  
Vol 29 (12) ◽  
pp. 1337-1344 ◽  
Author(s):  
Tomonori Sugiura ◽  
Yasuaki Dohi ◽  
Hiroyuki Takase ◽  
Sumiyo Yamashita ◽  
Yuji Tsuzuki ◽  
...  
Keyword(s):  
Observational Study ◽  
Binding Protein ◽  
Protein A ◽  
Serum Concentrations ◽  
Longitudinal Changes ◽  
Factors Associated

scholarly journals Whole-genome sequencing of the endemic Antarctic fungus Antarctomyces pellizariae reveals an ice-binding protein, a scarce set of secondary metabolites gene clusters and provides insights on Thelebolales phylogeny

Genomics ◽  
2020 ◽  
Vol 112 (5) ◽  
pp. 2915-2921 ◽  
Author(s):  
Thiago Mafra Batista ◽  
Heron Oliveira Hilario ◽  
Gabriel Antônio Mendes de Brito ◽  
Rennan Garcias Moreira ◽  
Carolina Furtado ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Binding Protein ◽  
Protein A ◽  
Gene Clusters ◽  
Whole Genome ◽  
Ice Binding ◽  
Ice Binding Protein

scholarly journals Consumption of a Double-Fortified Salt Affects Perceptual, Attentional, and Mnemonic Functioning in Women in a Randomized Controlled Trial in India

2017 ◽  
Vol 147 (12) ◽  
pp. 2297-2308 ◽  
Author(s):  
Michael J Wenger ◽  
Laura E Murray-Kolb ◽  
Julie EH Nevins ◽  
Sudha Venkatramanan ◽  
Gregory A Reinhart ◽  
...  
Keyword(s):  
Iron Deficiency ◽  
Iron Status ◽  
Controlled Trial ◽  
Reproductive Age ◽  
Deficiency Anemia ◽  
Control Group ◽  
Attention And Memory ◽  
Double Blind ◽  
Iron Deficient ◽  
Mnemonic Function

Abstract Background: Iron deficiency and iron deficiency anemia have been shown to have negative effects on aspects of perception, attention, and memory. Objective: The purpose of this investigation was to assess the extent to which increases in dietary iron consumption are related to improvements in behavioral measures of perceptual, attentional, and mnemonic function. Methods: Women were selected from a randomized, double-blind, controlled food-fortification trial involving ad libitum consumption of either a double-fortified salt (DFS) containing 47 mg potassium iodate/kg and 3.3 mg microencapsulated ferrous fumarate/g (1.1 mg elemental Fe/g) or a control iodized salt. Participants' blood iron status (primary outcomes) and cognitive functioning (secondary outcomes) were assessed at baseline and after 10 mo at endline. The study was performed on a tea plantation in the Darjeeling district of India. Participants (n = 126; 66% iron deficient and 49% anemic at baseline) were otherwise healthy women of reproductive age, 18–55 y. Results: Significant improvements were documented for iron status and for perceptual, attentional, and mnemonic function in the DFS group (percentage of variance accounted for: 16.5%) compared with the control group. In addition, the amount of change in perceptual and cognitive performance was significantly (P < 0.05) related to the amount of change in blood iron markers (mean percentage of variance accounted for: 16.0%) and baseline concentrations of blood iron markers (mean percentage of variance accounted for: 25.0%). Overall, there was evidence that the strongest effects of change in iron status were obtained for perceptual and low-level attentional function. Conclusion: DFS produced measurable and significant improvements in the perceptual, attentional, and mnemonic performance of Indian female tea pickers of reproductive age. This trial was registered at clinicaltrials.gov as NCT01032005.

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