Author/Editor		Bavec, Aljoša
Title		Strukturne značilnosti in delovanje nekaterih peptidnih antibiotikov
Translated title		Structure-activity relationships of some peptide antibiotics
Type		članek
Source		Med Razgl
Vol. and No.		Letnik 40, št. 2
Publication year		2001
Volume		str. 165-71
Language		slo
Abstract		Peptide antibiotics are a very heterogenic group of antibiotics. Among them we differ cyclic, linear, non-substituted or substituted peptide antibiotics. The main feature of almost all peptide antibiotics is their amphiphilicity. Primary structure of linear peptide antibiotics is defined as the covalent backbone structure of polypeptide chains, including the sequence of amino acid residues. The predominant structure of long length antibiotic peptides in an aqueous medium is the helical structure called alpha helix. Short length monomer peptides have very little secondary structure and exist mainly as a random coil. A typical amphipathic alpha helix is characterized by a flat hydrophobic and hydrophilic face along the axe of the molecule that interacts with polar and non-polar surfaces, like phospholipid bilayers, by packing around them in rigid, well-ordered, alpha helical arrangements. Cyclic peptide antibiotics show little potency for alpha helical conformation since they adopt bulky non-peptide groups. Rather, they express polar and non-polar regions that alternate with each other, form 'leafs' that resemble on beta sheets. Knowledge about structural characteristics of peptide antibiotics is very important for the development of new class of highly efficient antibiotic drugs.
Summary		Peptidni antibiotiki so po zgradbi zelo raznolika skupina antibiotikov. Poznamo linearne, ciklične, takšne z dodatnimi kemijskimi substituentami, vezane v obroču ali na obroč, in takšne brez njih. Skoraj vsem skupna lastnost je njihova amfipatičnost. Primarna struktura linearnih peptidnih antibiotikov pomeni niz aminokislin, ki si sledijo v zaporedju. Daljši monomerni peptidni antibiotiki ponavadi v vodni raztopini zavzamejo sekundarno strukturo alfa-heliksa, krajši pa obliko naključnega klobčiča. V stiku s polarnimi ali nepolarnimi površinami, na primer s fosfolipidnim dvoslojem, pa se struktura molekule uredi in delež alfa-heliksa se poveča oziroma molekula pridobi različne deleže sekundarnih struktur. Amfipatičnost se najbolje izrazi v obliki alfa-heliksa tako, da so vzdolž osi molekule na eni strani nanizane hidrofilne, na nasprotni strani pa hidrofobne aminokisline. Zaradi dodatnih kemijskih neaminokislinskih skupin je alfa-heliks manj pogost pri cikličnih peptidnih antibiotikih. Pri njih se oblikujejo večja hidrofilna in hidrofobna področja, ki so organizirana v nekakšne ploskve ali liste, ki se med seboj izmenjujejo in so podobna beta-strukturi. Omenjene strukturne lastnosti je treba upoštevati pri pridobivanju oz. kemijski sintezi novih peptidnih antibiotikov.
Descriptors		ANTIBIOTICS, PEPTIDE STRUCTURE-ACTIVITY RELATIONSHIP