Antimicrobial peptides: Difference between revisions

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==History==

Alexander Fleming first recognized the presence of a soluble antimicrobial substance produced by humans about 90 years ago. Discovered [[Lysozyme]] from nasal secretions from a patient suffering from acute coryza.

Subsequently, he found lysozyme antibacterial activity in various human physiological fluids and tissues of animals, as well as egg whites.

==Discovery and diversity==

Natural examples are found in all classes of organisms: animals including humans, invertebrate animals, plants, and fungi.�

So far more than 1,200 types of peptides with antimicrobial activity have been isolated from various cells and tissues.

==~~clasiffication~~==

For a partial list of these, see the Antimicrobial Peptide Database [http://aps.unmc.edu/AP/main.php]

==Clasiffication==

Antimicrobial peptides are divided into subgroups on the basis of their amino acid composition and structure (ref nature review).

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== Structural highlights ==

AMPs are rich with hydrophibic (Ala, Val, Ile, Leu, Met, Phe, Tyr, Trp) and Possitively charged (Lys, Arg) Amino Acids, which seems to allow them to bind into membranes. <scene name='67/676980/1pg1_arginine/1'>Protegrin 1</scene>, is a peptide from porcine leukocytes and it's sequence is rich with <scene name='67/676980/1pg1_hydrophobic_residues/1'> hydrophobic residues</scene> and <scene name='67/676980/1pg1_cationic_residues/1'>cationic residues</scene>.

AMPs ~~have a big vareity~~ of ~~structures, and these structures can be divided~~ to ~~a few categories: alpha helix structures, beta sheet structures, and peptides with extended or loop structures~~.

AMPs shared the abillity to attach membranes. Amino acids composition as well as the structure allow each of them to attach the microorganism's membrane.

~~Their structure~~ allow them to ~~interact with negatively charged phospholipid head groups of microbial~~ membranes~~, resulting in pore formation on the bacterial membrane~~ .

=Primary sequence=

~~Nevertheless, the way different antimicrobial peptides achieve their goal appears to be different~~, and ~~there are a few suggested mechanisms~~.

AMPs are rich with hydrophibic (Ala, Val, Ile, Leu, Met, Phe, Tyr, Trp) and Possitively charged (Lys, Arg) Amino Acids, which seems to allow them to bind into membranes. <scene name='67/676980/1pg1_arginine/1'>Protegrin 1</scene>, is a peptide from porcine leukocytes and it's sequence is rich with <scene name='67/676980/1pg1_hydrophobic_residues/1'> hydrophobic residues</scene> and <scene name='67/676980/1pg1_cationic_residues/1'>cationic residues</scene>.

=Secondary structure=

== AMPs structures ==

AMPs structure allows them to interact with negatively charged phospholipid head groups of microbial membranes, resulting in pore formation (or other mechanism, ) on the bacterial membrane .

Although AMPs have the same effect on the cell mambrane, they do not seem to have the same structure. we can find a big variety of structures among familiar AMPs.

~~As we mentioned earlier, Although AMPs have the same effect on the cell mambrane, they do not seem to have the same structure. we can find a big variety of structures among familiar AMPs.~~

(1) Some have '''helical structures''', for some of the peptide sequence, such as Magainin, (2LSA), or a helical structure throughout the whole peptide, such as Magainin2 (2MAG). this peptide was found on a frogs skin. you can see the page about Magainin2 here : [[2mag]].

(1) Some have helical structures, for some of the peptide sequence, such as Magainin, (2LSA), or a helical structure throughout the whole peptide, such as Magainin2 (2MAG). this peptide was found on a frogs skin. you can see the page about Magainin2 here : [[2mag]].

(2) Beta-sheet structures:

(2) '''Beta-sheet structures''':

<scene name='67/676980/1hvz_-_cyclic_peptide/1'>RTD1</scene>, A cyclic antimicrobial defencin from ''Rhesus Macaque leukocytes'',has a beta sheet structure, rich with disulfide bonds that strengthen the beta-sheet structure. this peptide is 55% beta sheet (4 strands; 10 residues).

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Protegrins are a family of arginine - and cysteine rich cationic peptides

(c) and some have combined structures, like <scene name='67/676980/1ijv_lysin/1'>Human beta defencin1</scene>

(c) and some have '''combined structures''', like <scene name='67/676980/1ijv_lysin/1'>Human beta defencin1</scene>

==Suggested Mechanisms==

The way different antimicrobial peptides achieve their goal appears to be different, and there are a few suggested mechanisms.

~~==Suggested Mechanisms==~~

There are a few suggested machanisms of how AMPs work(William C. Wimley,

Antimicrobial peptides: Difference between revisions

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@@ Line 13: / Line 13: @@
 ==History==
+Alexander Fleming first recognized the presence of a soluble antimicrobial substance produced by humans about 90 years ago. Discovered [[Lysozyme]] from nasal secretions from a patient suffering from acute coryza.
+Subsequently, he found lysozyme antibacterial activity in various human physiological fluids and tissues of animals, as well as egg whites.
 ==Discovery and diversity==
+Natural examples are found in all classes of organisms: animals including humans, invertebrate animals, plants, and fungi.�
+So far more than 1,200 types of peptides with antimicrobial activity have been isolated from various cells and tissues.
-==clasiffication==
+ For a partial list of these, see the Antimicrobial Peptide Database [http://aps.unmc.edu/AP/main.php]
+==Clasiffication==
 Antimicrobial peptides are divided into subgroups on the basis of their amino acid composition and structure (ref nature review).
@@ Line 98: / Line 107: @@
 == Structural highlights ==
-AMPs are rich with hydrophibic (Ala, Val, Ile, Leu, Met, Phe, Tyr, Trp) and Possitively charged (Lys, Arg) Amino Acids, which seems to allow them to bind into membranes. <scene name='67/676980/1pg1_arginine/1'>Protegrin 1</scene>, is a peptide from porcine leukocytes and it's sequence is rich with <scene name='67/676980/1pg1_hydrophobic_residues/1'> hydrophobic residues</scene> and <scene name='67/676980/1pg1_cationic_residues/1'>cationic residues</scene>.
-AMPs have a big vareity of structures, and these structures can be divided to a few categories: alpha helix structures, beta sheet structures, and peptides with extended or loop structures.
+AMPs shared the abillity to attach membranes. Amino acids composition as well as the structure allow each of them to attach the microorganism's membrane.
-Their structure allow them to interact with negatively charged phospholipid head groups of microbial membranes, resulting in pore formation on the bacterial membrane .
+=Primary sequence=
-Nevertheless, the way different antimicrobial peptides achieve their goal appears to be different, and there are a few suggested mechanisms.
+AMPs are rich with hydrophibic (Ala, Val, Ile, Leu, Met, Phe, Tyr, Trp) and Possitively charged (Lys, Arg) Amino Acids, which seems to allow them to bind into membranes. <scene name='67/676980/1pg1_arginine/1'>Protegrin 1</scene>, is a peptide from porcine leukocytes and it's sequence is rich with <scene name='67/676980/1pg1_hydrophobic_residues/1'> hydrophobic residues</scene> and <scene name='67/676980/1pg1_cationic_residues/1'>cationic residues</scene>.
+=Secondary structure=
-== AMPs structures ==
+AMPs structure allows them to interact with negatively charged phospholipid head groups of microbial membranes, resulting in pore formation (or other mechanism, ) on the bacterial membrane .
+Although AMPs have the same effect on the cell mambrane, they do not seem to have the same structure. we can find a big variety of structures among familiar AMPs.
-As we mentioned earlier, Although AMPs have the same effect on the cell mambrane, they do not seem to have the same structure. we can find a big variety of structures among familiar AMPs.
+(1) Some have '''helical structures''', for some of the peptide sequence, such as Magainin, (2LSA), or a helical structure throughout the whole peptide, such as Magainin2 (2MAG). this peptide was found on a frogs skin. you can see the page about Magainin2 here : [[2mag]].
-(1) Some have helical structures, for some of the peptide sequence, such as Magainin, (2LSA), or a helical structure throughout the whole peptide, such as Magainin2 (2MAG). this peptide was found on a frogs skin. you can see the page about Magainin2 here : [[2mag]].
-(2) Beta-sheet structures:
+(2) '''Beta-sheet structures''':
 <scene name='67/676980/1hvz_-_cyclic_peptide/1'>RTD1</scene>, A cyclic antimicrobial defencin from ''Rhesus Macaque leukocytes'',has a beta sheet structure, rich with disulfide bonds that strengthen the beta-sheet structure. this peptide is 55% beta sheet (4 strands; 10 residues).
@@ Line 118: / Line 127: @@
 Protegrins are a family of arginine - and cysteine rich cationic peptides
-(c) and some have combined structures, like <scene name='67/676980/1ijv_lysin/1'>Human beta defencin1</scene>
+(c) and some have '''combined structures''', like <scene name='67/676980/1ijv_lysin/1'>Human beta defencin1</scene>
+==Suggested Mechanisms==
+The way different antimicrobial peptides achieve their goal appears to be different, and there are a few suggested mechanisms.
-==Suggested Mechanisms==
 There are a few suggested machanisms of how AMPs work(William C. Wimley,