Synthesis and Evaluation of Bifunctional sGC Regulators: Optimization of a Connecting Linker

Abstract

Hybrid molecules composed of PpIX and cobyrinic acid derivatives conjugated through linkers of varying length and composition were prepared via 1,3-dipolar cycloaddition (CuAAC) or amidation/esteryfication reactions. They were tested for activation of soluble guanylyl cyclase (sGC), a key enzyme in the NO/cGMP signaling pathway, by an in vitro GTP→cGMP conversion assay. Using purified heme-deficient sGC and truncated sGC variants lacking a heme-binding domain, we demonstrated that such hybrid molecules may activate sGC by targeting heme-binding and/or catalytic domain. While all conjugates activated sGC, only selected compounds served as bifunctional regulators and were capable of simultaneous targeting both heme and catalytic domains of sGC. The length and type of a linker connecting both components had a profound effect on the extent of sGC activation, indicating that the linker's type is crucial for their binding affinities with regulatory and catalytic domains. Only hybrids with the conjugated linker of 13-16 atom length synergistically target both domains and displayed the lowest EC50 and highest activating potency. Compounds with shorter connecting linkers were much less potent and were no more active than the cobyrinic acid component alone. The most active conjugate, which showed a 60-fold activation of sGC, was compound 11, in which PpIX and cobyrinic acid components are separated by 11 atoms chain with the triazole moiety in between.

Recent trends in the development of vitamin B12derivatives for medicinal applications

“…Base-off forms of Cob(III)-, and Cob(II)alamins can also be obtained by substituting the intramolecularly bound Dmbz base with competitive ligands, for example with water. This derivative was initially developed as a hydrophobic B 12 mimic in the group of Eschenmoser (Figure 4) 23,24 and has nowadays found new applications as photocatalyst, [25][26][27] chemosensor (see chapter 2.1), 17, 28-31 enzyme activators (see chapter 2.4) 32,33 and is also used for fundamental studies 8, 16, 34-38 . In this equilibrium (Figure 3), 13 a low pK base-off value reflects a favoured intramolecular coordination of the Dmbz base to the metal-centre, e.g.…”

“…33,62 For this purpose, cobyrinic acid and PpIX were connected to each other with linkers of different compositions and lengths. 33,62 For this purpose, cobyrinic acid and PpIX were connected to each other with linkers of different compositions and lengths.…”

“…33,62 For this purpose, cobyrinic acid and PpIX were connected to each other with linkers of different compositions and lengths. 33 Considering the vast possibilities of further structural variations, significant progress is expected in this area in the near future. 33 Considering the vast possibilities of further structural variations, significant progress is expected in this area in the near future.…”

The fibrate gemfibrozil is a NO‐ and haem‐independent activator of soluble guanylyl cyclase: in vitro studies

“…Cinaciguat is considered for treatment of heart failure (Zamani and Greenberg, 2013), although some side effects are yet to be resolved (Erdmann et al, 2013a). The effects of both sGC stimulators and haem-independent activators are enhanced by cobinamides, which act independently of sGC haem and its haem-binding region (Sharina et al, 2011a;Chrominski et al, 2013).…”

Modified vitamin B12 derivatives with a peptide backbone for biomimetic studies and medicinal applications

“…This short review focuses on the author's group efforts in the development of modified B 12 derivatives with a peptide backbone as models of cofactor-protein complexes as well as for medicinal and biological applications. For more comprehensive insight into the topic including the uptake, metabolism and reactivity of Cbls in biological systems [3,7,8,17,[19][20][21], the development of B 12 derivatives as biomimetic models [22][23][24][25][26][27][28], or the use of Cbls for medical [2,[29][30][31][32][33][34][35][36][37][38][39][40] and analytical applications [41][42][43][44][45][46], the interested reader is referred to the original literature as well as to several excellent reviews and book chapters [2,3,8,[47][48][49][50][51].…”