Lactoferrampin, an antimicrobial peptide of bovine lactoferrin, exerts its candidacidal activity by a cluster of positively charged residues at the C-terminus in combination with a helix-facilitating N-terminal part

2005 ◽  
Vol 386 (2) ◽  
pp. 137-142 ◽  
Author(s):  
Marieke I.A. van der Kraan ◽  
Kamran Nazmi ◽  
Afke Teeken ◽  
Jasper Groenink ◽  
Wim van 't Hof ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Candida Albicans ◽  
Antimicrobial Peptide ◽  
Helical Conformation ◽  
Bovine Lactoferrin ◽  
Terminal Part ◽  
Helix Formation ◽  
C Terminus ◽  
Charged Residues ◽  
Positively Charged

AbstractThe antimicrobial activity of bovine lactoferrin (bLF) is attributed to lactoferricin, which is situated in the N1-domain of bLF. Recently, another antimicrobial domain consisting of residues 268–284, designated lactoferrampin (LFampin), has been identified in the N1-domain of bLF, which exhibited antimicrobial activity againstCandida albicansand several bacteria. In the present study, the candidacidal activity of a series of peptides spanning this antimicrobial domain was investigated in relation to the charge and the capacity to form a helical conformation in hydrophobic environments. C-Terminal truncation of LFampin resulted in a drastic decrease in candidacidal activity. Positively charged residues clustered at the C-terminal side of the LFampin domain appeared to be crucial for the candidacidal activity. The ability to adopt helical conformations did not change when LFampin was truncated at the C-terminal side. N-Terminally truncated LFampin peptides, truncated up to the sequence 270–284, were more reluctant to adopt a helical conformation. Therefore, we conclude that the C-terminal part of LFampin 265–284, which is the most active peptide, is crucial for its candidacidal activity, due to the presence of clustered positive charges, and that the N-terminal part is essential for activity as it facilitates helix formation.

scholarly journals Clusters of Charged Residues at the C Terminus of MotA and N Terminus of MotB Are Important for Function of the Escherichia coli Flagellar Motor

2008 ◽  
Vol 190 (15) ◽  
pp. 5517-5521 ◽  
Author(s):  
Edan R. Hosking ◽  
Michael D. Manson
Keyword(s):  
Escherichia Coli ◽  
Flagellar Motor ◽  
Protein Levels ◽  
Partner Protein ◽  
C Terminus ◽  
N Terminus ◽  
Charged Residues ◽  
Positively Charged ◽  
Terminal Cluster

ABSTRACT MotA contains a conserved C-terminal cluster of negatively charged residues, and MotB contains a conserved N-terminal cluster of positively charged residues. Charge-altering mutations affecting these residues impair motility but do not diminish Mot protein levels. The motility defects are reversed by second-site mutations targeting the same or partner protein.

scholarly journals Design of Novel Amphipathic α-Helical Antimicrobial Peptides with No Toxicity as Therapeutics against the Antibiotic-Resistant Gram-Negative Bacterial Pathogen, Acinetobacter Baumannii

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Mant CT ◽  
Jiang Z ◽  
Gera L ◽  
Davis T ◽  
Hodges RS
Keyword(s):  
Antimicrobial Activity ◽  
Antimicrobial Peptides ◽  
Acinetobacter Baumannii ◽  
De Novo ◽  
Bacterial Pathogen ◽  
Polymyxin B ◽  
Hemolysis Assay ◽  
Charged Residues ◽  
Positively Charged ◽  
Specificity Determinants

We designed de novo and synthesized two series of five 26-residue amphipathic α-helical cationic antimicrobial peptides (AMPs) with five or six positively charged residues (D-Lys, L-Dab (2,4-diaminobutyric acid) or L-Dap (2,3-diaminopropionic acid)) on the polar face where all other residues are in the D-conformation. Hemolytic activity against human red blood cells was determined using the most stringent conditions for the hemolysis assay, 18h at 37°C, 1% human erythrocytes and peptide concentrations up to 1000 μg/mL (~380 μM). Antimicrobial activity was determined against 7 Acinetobacter baumannii strains, resistant to polymyxin B and colistin (antibiotics of last resort) to show the effect of positively charged residues in two different locations on the polar face (positions 3, 7, 11, 18, 22 and 26 versus positions 3, 7, 14, 15, 22 and 26). All 10 peptides had two D-Lys residues in the center of the non-polar face as “specificity determinants” at positions 13 and 16 which provide specificity for prokaryotic cells over eukaryotic cells. Specificity determinants also maintain excellent antimicrobial activity in the presence of human sera. This study shows that the location and type of positively charged residue (Dab and Dap) on the polar face are critical to obtain the best therapeutic indices.

scholarly journals The Interactions between the Antimicrobial Peptide P-113 and Living Candida albicans Cells Shed Light on Mechanisms of Antifungal Activity and Resistance

2020 ◽  
Vol 21 (7) ◽  
pp. 2654 ◽  
Author(s):  
Kuang-Ting Cheng ◽  
Chih-Lung Wu ◽  
Bak-Sau Yip ◽  
Ya-Han Chih ◽  
Kuang-Li Peng ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Antifungal Activity ◽  
Antimicrobial Peptide ◽  
Oral Candidiasis ◽  
Immune Deficiency Syndrome ◽  
Deficiency Syndrome ◽  
Salivary Protein ◽  
Histatin 5 ◽  
C Terminus

In the absence of proper immunity, such as in the case of acquired immune deficiency syndrome (AIDS) patients, Candida albicans, the most common human fungal pathogen, may cause mucosal and even life-threatening systemic infections. P-113 (AKRHHGYKRKFH), an antimicrobial peptide (AMP) derived from the human salivary protein histatin 5, shows good safety and efficacy profiles in gingivitis and human immunodeficiency virus (HIV) patients with oral candidiasis. However, little is known about how P-113 interacts with Candida albicans or its degradation by Candida-secreted proteases that contribute to the fungi’s resistance. Here, we use solution nuclear magnetic resonance (NMR) methods to elucidate the molecular mechanism of interactions between P-113 and living Candida albicans cells. Furthermore, we found that proteolytic cleavage of the C-terminus prevents the entry of P-113 into cells and that increasing the hydrophobicity of the peptide can significantly increase its antifungal activity. These results could help in the design of novel antimicrobial peptides that have enhanced stability in vivo and that can have potential therapeutic applications.

scholarly journals ANKRD22 is an N-myristoylated hairpin-like monotopic membrane protein specifically localized to lipid droplets

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Toshihiko Utsumi ◽  
Takuro Hosokawa ◽  
Mayu Shichita ◽  
Misato Nishiue ◽  
Natsuko Iwamoto ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Lipid Droplets ◽  
Transmembrane Domain ◽  
Intracellular Localization ◽  
Membrane Topology ◽  
Intracellular Targeting ◽  
C Terminus ◽  
Charged Residues ◽  
Necrosis Factor ◽  
Positively Charged

AbstractThe membrane topology and intracellular localization of ANKRD22, a novel human N-myristoylated protein with a predicted single-pass transmembrane domain that was recently reported to be overexpressed in cancer, were examined. Immunofluorescence staining of COS-1 cells transfected with cDNA encoding ANKRD22 coupled with organelle markers revealed that ANKRD22 localized specifically to lipid droplets (LD). Analysis of the intracellular localization of ANKRD22 mutants C-terminally fused to glycosylatable tumor necrosis factor (GLCTNF) and assessment of their susceptibility to protein N-glycosylation revealed that ANKRD22 is synthesized on the endoplasmic reticulum (ER) membrane as an N-myristoylated hairpin-like monotopic membrane protein with the amino- and carboxyl termini facing the cytoplasm and then sorted to LD. Pro98 located at the center of the predicted membrane domain was found to be essential for the formation of the hairpin-like monotopic topology of ANKRD22. Moreover, the hairpin-like monotopic topology, and positively charged residues located near the C-terminus were demonstrated to be required for the sorting of ANKRD22 from ER to LD. Protein N-myristoylation was found to positively affect the LD localization. Thus, multiple factors, including hairpin-like monotopic membrane topology, C-terminal positively charged residues, and protein N-myristoylation cooperatively affected the intracellular targeting of ANKRD22 to LD.

scholarly journals ANTIMICROBIAL ACTIVITY OF THE HUMAN AND BOVINE LACTOFERRIN AGAINST GRAM-POSITIVE BACTERIA AND CANDIDA ALBICANS

2018 ◽  
pp. 54-58
Author(s):  
V. N. Zorina ◽  
O. N. Vorobeva ◽  
N. A. Zorin
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Candida Albicans ◽  
Minimum Inhibitory Concentration ◽  
Staphylococcus Epidermidis ◽  
Inhibitory Concentration ◽  
Physiological Solution ◽  
Bovine Lactoferrin ◽  
Gram Positive Bacteria ◽  
High Doses

Aim. A comparative study of the effect ofbovine and human lactoferrin (LF) on Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Candida albicans strains. Materials and methods. The daily agar cultures of museum and clinical strains of microorganisms were standardized, diluted with physiological solution up (from 5000 microbial cells/ ml to 0.1 ml) was added to the stepwise dilution of LF (from 1000 pg /ml) and incubated 18 - 24 hours at 37°C. The amount of LF in the sample with the total apparent growth retardation of the microbes was the minimum inhibitory concentration (MIC) for the strain. Results. The MIC of human LF was 4 - 8 times less than MIC of bovine LF. The smallest dose was required for the suppression of C. albicans (11.3±1.5 and 43.8±9.5 pg/ml respectively), the largest when using human LF was needed to suppress S. aureus (38,2±4,6), and in a case of bovine LF - E. faecalis (206,3±51,1). Conclusion. Human LF is much more effective in suppressing bacterial infection, but in the course of evolution, there is an increase in the resistance of S. aureus to LF. The higher availability of bovine LF and the lack of a tendency to increase resistance, it is advisable to use high-doses of bovine LF in the treatment of resistant forms of bacteria and C. albicans.

Activity of Synthetic Antimicrobial Peptide GH12 against Oral Streptococci

2016 ◽  
Vol 50 (1) ◽  
pp. 48-61 ◽  
Author(s):  
Huanxin Tu ◽  
Yingying Fan ◽  
Xueping Lv ◽  
Sili Han ◽  
Xuedong Zhou ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Antimicrobial Peptide ◽  
Biofilm Formation ◽  
Laser Scanning ◽  
Reversed Phase ◽  
Laser Scanning Microscopy ◽  
Helical Conformation ◽  
Confocal Laser ◽  
Oral Streptococci

Controlling the growth of cariogenic microorganisms such as oral streptococci is an adjunct therapy for caries-active individuals to prevent and treat caries. Here we investigated the antimicrobial activity of the synthetic amphipathic α- helical antimicrobial peptide GH12 (GLLWHLLHHLLH-NH2) against oral streptococci in vitro. Circular dichroism studies showed that GH12 takes on an α-helical conformation in the presence of membrane-mimicking solvents, and reversed-phase high-performance liquid chromatography studies showed that GH12 remains stable in saliva. The peptide showed bactericidal activity against oral streptococci, with minimum inhibitory concentrations ranging from 6.7 to 32.0 μg/ml. GH12 concentrations 4-fold higher than the minimum bactericidal concentration completely killed oral streptococci within 20 min. Treating oral streptococci with GH12 caused noticeable changes in bacterial viability and morphology based on confocal laser scanning microscopy and scanning electron microscopy. Effects of GH12 on biofilm formation and on viability of mature biofilm were quantified by crystal violet staining and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. GH12 effectively inhibited biofilm formation and metabolic activity in biofilms of oral streptococci, especially S. mutans, S. sobrinus and S. salivarius. These results suggest that GH12 shows rapid and strong antimicrobial activity against oral streptococci in vitro, opening the door to preclinical and clinical studies to explore its potential for caries prevention and treatment.

scholarly journals The Flexible and Clustered Lysine Residues of Human Ribonuclease 7 Are Critical for Membrane Permeability and Antimicrobial Activity

2006 ◽  
Vol 282 (7) ◽  
pp. 4626-4633 ◽  
Author(s):  
Yu-Chie Huang ◽  
Yu-Min Lin ◽  
Ting-Wei Chang ◽  
Shih-Jung Wu ◽  
Yan-Shin Lee ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Bacterial Membrane ◽  
Nmr Studies ◽  
Charged Residues ◽  
Lysine Residues ◽  
Flexible Coil ◽  
Rnase Treatment ◽  
Cationic Residues ◽  
Positively Charged

The ubiquitous ribonucleases (RNases) play important roles in RNA metabolism, angiogenesis, neurotoxicity, and antitumor or antimicrobial activity. Only the antimicrobial RNases possess high positively charged residues, although their mechanisms of action remain unclear. Here, we report on the role of cationic residues of human RNase7 (hRNase7) in its antimicrobial activity. It exerted antimicrobial activity against bacteria and yeast, even at 4 °C. The bacterial membrane became permeable to the DNA-binding dye SYTOX® Green in only a few minutes after bactericidal RNase treatment. NMR studies showed that the 22 positively charged residues (Lys18 and Arg4) are distributed into three clusters on the surface of hRNase7. The first cluster, K1,K3,K111,K112, was located at the flexible coil near the N terminus, whereas the other two, K32,K35 and K96,R97,K100, were located on rigid secondary structures. Mutagenesis studies showed that the flexible cluster K1,K3,K111,K112, rather than the catalytic residues His15, Lys38, and His123 or other clusters such as K32,K35 and K96,R97,K100, is critical for the bactericidal activity. We suggest that the hRNase7 binds to bacterial membrane and renders the membrane permeable through the flexible and clustered Lys residues K1,K3,K111,K112. The conformation of hRNase7 can be adapted for pore formation or disruption of bacterial membrane even at 4 °C.

Killing of Candida albicans by lactoferricin B, a potent antimicrobial peptide derived from the N-terminal region of bovine lactoferrin

1993 ◽  
Vol 182 (2) ◽  
Author(s):  
Wayne Bellamy ◽  
Hiroyuki Wakabayashi ◽  
Mitsunori Takase ◽  
Kouzou Kawase ◽  
Seiichi Shimamura ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Antimicrobial Peptide ◽  
Terminal Region ◽  
Bovine Lactoferrin

scholarly journals The positive inside rule is stronger when followed by a transmembrane helix.

2015 ◽  
Author(s):  
Minttu T Virkki ◽  
Christoph Peters ◽  
Daniel Nilsson ◽  
Therese Sörensen ◽  
Susana Cristobal ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Transmembrane Helix ◽  
Specific Interactions ◽  
Transmembrane Helices ◽  
Terminal Part ◽  
Naturally Occurring ◽  
Charged Residues ◽  
Hydrophobic Helices ◽  
Hydrophobic Helix ◽  
Positively Charged

The translocon recognizes transmembrane helices with sufficient level of hydrophobicity and inserts them into the membrane. However, sometimes less hydrophobic helices are also recognized. Positive inside rule, orientational preferences of and specific interactions with neighboring helices have been shown to aid in the recognition of these helices, at least in artificial systems. To better understand how the translocon inserts marginally hydrophobic helices, we studied three \red{naturally occurring marginally hydrophobic} helices, which were previously shown to require the subsequent helix for efficient translocon recognition. We find no evidence for specific interactions when we scan all residues in the subsequent helices. Instead, we identify arginines located at the N-terminal part of the subsequent helices that are crucial for the recognition of the marginally hydrophobic transmembrane helices, indicating that the positive inside rule is important. However, in two of the constructs these arginines do not aid in the recognition without the rest of the subsequent helix, i.e. the positive inside rule alone is not sufficient. Instead, the improved recognition of marginally hydrophobic helices can here be explained as follows; the positive inside rule provides an orientational preference of the subsequent helix, which in turn allows the marginally hydrophobic helix to be inserted, i.e. the effect of the positive inside rule is stronger if positively charged residues are followed by a transmembrane helix. Such a mechanism can obviously not aid C-terminal helices and consequently we find that the terminal helices in multi-spanning membrane proteins are more hydrophobic than internal helices.

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