Interrelations Between Side Chain and Main Chain Packing in Different Crystal Modifications of Alkoxylated Polyesters

2017 ◽  
Vol 121 (17) ◽  
pp. 4583-4591 ◽  
Author(s):  
Gaurav Gupta ◽  
Varun Danke ◽  
Tamoor Babur ◽  
Mario Beiner
Keyword(s):  
Main Chain ◽  
Side Chain ◽  
Chain Packing ◽  
Crystal Modifications

scholarly journals Too packed to change: site-specific substitution rates and side-chain packing in protein evolution

2014 ◽  
Author(s):  
María Laura Marcos ◽  
Julian Echave
Keyword(s):  
Protein Evolution ◽  
Packing Density ◽  
Main Chain ◽  
Side Chain ◽  
Side Chains ◽  
Contact Density ◽  
Chain Packing ◽  
Site Specific ◽  
Stress Theory ◽  
Side Chain Packing

In protein evolution, due to functional and biophysical constraints, the rates of amino acid substitution differ from site to site. Among the best predictors of site-specific rates is packing density. The packing density measure that best correlates with rates is the weighted contact number (WCN), the sum of inverse square distances between the site’s Cαand the other Cαs . According to a mechanistic stress model proposed recently, rates are determined by packing because mutating packed sites stresses and destabilizes the protein’s active conformation. While WCN is a measure of Cαpacking, mutations replace side chains, which prompted us to consider whether a site’s evolutionary divergence is constrained by main-chain packing or side-chain packing. To address this issue, we extended the stress theory to model side chains explicitly. The theory predicts that rates should depend solely on side-chain packing. We tested these predictions on a data set of structurally and functionally diverse monomeric enzymes. We found that, on average, side-chain contact density (WCNρ) explains 39.1% of among-sites rate variation, larger than main-chain contact density (WCNα) which explains 32.1%. More importantly, the independent contribution of WCNαis only 0.7%. Thus, as predicted by the stress theory, site-specific evolutionary rates are determined by side-chain packing.

scholarly journals Substrate Scope for Human Histone Lysine Acetyltransferase KAT8

2021 ◽  
Vol 22 (2) ◽  
pp. 846
Author(s):  
Giordano Proietti ◽  
Yali Wang ◽  
Chiara Punzo ◽  
Jasmin Mecinović
Keyword(s):  
Main Chain ◽  
Coenzyme A ◽  
Side Chain ◽  
Histone H4 ◽  
Chemical Probes ◽  
Acetyl Coenzyme A ◽  
Acetyl Coenzyme ◽  
Histone Lysine ◽  
Lysine Acetyltransferase

Biomedically important histone lysine acetyltransferase KAT8 catalyses the acetyl coenzyme A-dependent acetylation of lysine on histone and other proteins. Here, we explore the ability of human KAT8 to catalyse the acetylation of histone H4 peptides possessing lysine and its analogues at position 16 (H4K16). Our synthetic and enzymatic studies on chemically and structurally diverse lysine mimics demonstrate that KAT8 also has a capacity to acetylate selected lysine analogues that possess subtle changes on the side chain and main chain. Overall, this work highlights that KAT8 has a broader substrate scope beyond natural lysine, and contributes to the design of new chemical probes targeting KAT8 and other members of the histone lysine acetyltransferase (KAT) family.

scholarly journals Side-Chain to Main-Chain Hydrogen Bonding Controls the Intrinsic Backbone Dynamics of the Amyloid Precursor Protein Transmembrane Helix

2014 ◽  
Vol 106 (6) ◽  
pp. 1318-1326 ◽  
Author(s):  
Christina Scharnagl ◽  
Oxana Pester ◽  
Philipp Hornburg ◽  
Daniel Hornburg ◽  
Alexander Götz ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Amyloid Precursor Protein ◽  
Main Chain ◽  
Transmembrane Helix ◽  
Precursor Protein ◽  
Backbone Dynamics ◽  
Side Chain

scholarly journals Synthesis and Photochemical Reaction of Polymers Containing Norbornadiene Residues Both in the Main Chain and Side Chain.

2000 ◽  
Vol 57 (9) ◽  
pp. 569-576 ◽  
Author(s):  
Makoto SAMPEI ◽  
Ken HIRAMATU ◽  
Atsushi KAMEYAMA ◽  
Tadatomi NISHIKUBO
Keyword(s):  
Photochemical Reaction ◽  
Main Chain ◽  
Side Chain

Thermosetting Mechanism Study of Organosilicon Polymer Containing Carborane by Solid-State NMR Spectroscopy

1999 ◽  
Vol 576 ◽  
Author(s):  
H. Kimura ◽  
K. Okita ◽  
M. Ichitani ◽  
M. Yonezawa ◽  
T. Sugimoto
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Nmr Spectra ◽  
Main Chain ◽  
Addition Reaction ◽  
Side Chain ◽  
Mechanism Study ◽  
Nmr Method ◽  
Organosilicon Polymer ◽  
Thermal Stable

ABSTRACTThe thermosetting mechanism of an organosilicon polymer containing carborane has been studied utilizing the 13and 29Si solid-state NMR method. The polymer having C≡C bonds in the main chain and CH═CH2, Si-H bonds, and carborane in the bulky side chain, shows a very highly thermal stability in air by curing. From 13C and 29Si NMR spectra of the polymer, it was found that the intermolecular cross-linking reactions of the polymer was due to (1) the diene reaction between Ph-C≡C and C≡C and (2) the addition reaction between side chain terminal and Ph-C≡C and between CH═CH2 and Si–H, and a very highly thermal stable structure is formed.

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