Structures of some of the minor aminoglycoside factors of the nebramycin fermentation

Abstract

The structures of some of the minor factors of the nebramycin complex of antibiotics are elucidated through a combination of physical and chemical methods.

Aminoglycoside binding in the major groove of duplex RNA: the thermodynamic and electrostatic forces that govern recognition

“…Inspection of the data in Table 1 reveals a ÁH b of À2.2 kcal/mol at pH 5.5. Note that tobramycin is essentially 100 % protonated at this pH (Dorman et al, 1976;Koch et al, 1978). Thus, our observed binding enthalpy at pH 5.5 (À2.2 kcal/mol) re¯ects the intrinsic heat associated with the binding of the pentacationic form of tobramycin to the host p(rI) Áp(rC) duplex.…”

“…The structure of tobramycin in which the atomic and ring numbering systems are denoted in Arabic and Roman numerals, respectively. The NMRderived (Dorman et al, 1976;Koch et al, 1978) pK a values of the ®ve amino groups are indicated.…”

A comprehensive review of glycosylated bacterial natural products

“…In addition to a few sugars highlighted in the previous paragraph found appended at C-6 of aminoglycoside core aglycons ( 2 , 4 , 8 , 10 , 12 ), 54,62,63 additional sugar diversity has been found at C-6 including: α-D-glucose ( 18 ); 64 3′-amino-3′-deoxy-α-D-xylose 21 (gentamicins and sisomicins) 37,65 and its C-4′-methyl branched 19 (prevalent in a range of aminoglycosides); 51,66,67 C-4′-methyl branched 3′-amino-3′-deoxy-α-D-galactose 20 (combimicins); 56 3′-amino-3′-deoxy-β-L-arabinose ( 22 , gentamicins and related compounds); 37,65 2′-amino-2′-deoxy-α-D-xylose 24 and its corresponding 2′,3′-diamino-2′,3′-dideoxy analog 23 (seldomycins); 58,68 as well as 3′-amino-3′-deoxy-β-D-mannose ( 42 ) and the diasaccharide I [comprised of the uniquely C-6′ oxidized mannose 43 and 2′-amino-2′-deoxy-α-D-xylose ( 24 ) in boholmycin]. 50 Other C-6′-appended sugars include L-streptose ( 28 ), 5′-hydroxy-L-streptose ( 30 ) and the corresponding reduced forms 29 and 31 have been found among streptomycins 69–71 wherein further C-2′ glycosylation of the streptose moiety with 2′-amino-2′-deoxy-α-L-glucose ( 32 ) has been observed.…”

Molecular Determinants of Antibiotic Recognition and Resistance by Aminoglycoside Phosphotransferase (3′)-IIIa: A Calorimetric and Mutational Analysis

“…The solution conditions for the AMP-PNP ITC experiments contained 10 mM buffer (Epps or Taps) at pH 8.0, 100 mM KCl, 5 mM MgCl 2 , and 0.01% TWEEN 80. 15 [21][22][23] Amino pK a values were determined from plots of the pH dependence of 15 N chemical shifts (δ) by non-linear least squared analyses using the following relationship:…”