Coordination of Biologically Important α-Amino Acids to Calcium(II) at High pH:  Insights from Crystal Structures of Calcium α-Aminocarboxylates

2007 ◽  
Vol 46 (3) ◽  
pp. 818-824 ◽  
Author(s):  
Stefan Fox ◽  
Insa Büsching ◽  
Walter Barklage ◽  
Henry Strasdeit
2016 ◽  
Vol 113 (26) ◽  
pp. 7160-7165 ◽  
Author(s):  
Oliver J. Harrison ◽  
Julia Brasch ◽  
Gorka Lasso ◽  
Phinikoula S. Katsamba ◽  
Goran Ahlsen ◽  
...  

Desmosomes are intercellular adhesive junctions that impart strength to vertebrate tissues. Their dense, ordered intercellular attachments are formed by desmogleins (Dsgs) and desmocollins (Dscs), but the nature of trans-cellular interactions between these specialized cadherins is unclear. Here, using solution biophysics and coated-bead aggregation experiments, we demonstrate family-wise heterophilic specificity: All Dsgs form adhesive dimers with all Dscs, with affinities characteristic of each Dsg:Dsc pair. Crystal structures of ectodomains from Dsg2 and Dsg3 and from Dsc1 and Dsc2 show binding through a strand-swap mechanism similar to that of homophilic classical cadherins. However, conserved charged amino acids inhibit Dsg:Dsg and Dsc:Dsc interactions by same-charge repulsion and promote heterophilic Dsg:Dsc interactions through opposite-charge attraction. These findings show that Dsg:Dsc heterodimers represent the fundamental adhesive unit of desmosomes and provide a structural framework for understanding desmosome assembly.


2000 ◽  
Vol 39 (24) ◽  
pp. 5437-5443 ◽  
Author(s):  
Alexandra Hess ◽  
Jan Sehnert ◽  
Thomas Weyhermüller ◽  
Nils Metzler-Nolte

2015 ◽  
Vol 39 (5) ◽  
pp. 3319-3326 ◽  
Author(s):  
Madhusudana M. B. Reddy ◽  
K. Basuroy ◽  
S. Chandrappa ◽  
B. Dinesh ◽  
B. Vasantha ◽  
...  

γn amino acid residues can be incorporated into structures in γn and hybrid sequences containing folded and extended α and δ residues.


2002 ◽  
Vol 58 (6) ◽  
pp. 1051-1056 ◽  
Author(s):  
N. T. Saraswathi ◽  
M. Vijayan

The crystal structures of the complexes of malonic acid with DL- and L-arginine, which contain positively charged argininium ions and negatively charged semimalonate ions, further demonstrate the conformational flexibility of amino acids. A larger proportion of folded conformations than would be expected on the basis of steric consideration appears to occur in arginine, presumably because of the requirements of hydrogen bonding. The aggregation pattern in the DL-arginine complex bears varying degrees of resemblance to patterns observed in other similar structures. An antiparallel hydrogen-bonded dimeric arrangement of arginine, and to a lesser extent lysine, is a recurring motif. Similarities also exist among the structures in the interactions with this motif and its assembly into larger features of aggregation. However, the aggregation pattern observed in the L-arginine complex differs from any observed so far, which demonstrates that all the general patterns of amino-acid aggregation have not yet been elucidated. The two complexes represent cases where the reversal of the chirality of half the amino-acid molecules leads to a fundamentally different aggregation pattern.


Author(s):  
Nikolay V. Dokholyan ◽  
Jose M. Borreguero ◽  
Sergey V. Buldyrev ◽  
Feng Ding ◽  
H.Eugene Stanley ◽  
...  

2019 ◽  
Vol 59 (6) ◽  
pp. 1155 ◽  
Author(s):  
D. R. Kang ◽  
S. A. Belal ◽  
E. S. R. Cho ◽  
H. N. Kang ◽  
J. H. Jung ◽  
...  

This study was carried out to investigate the influence of pH on the Berkshire’s pork longissimus dorsi muscle, by comparing physicochemical characteristics in a high pH group (5.92 ± 0.02) and a low pH group (5.55 ± 0.03) on the basis of muscle pH24 h post-mortem. Fifteen pigs were assigned to each group (n = 15). The low pH group showed higher filter-paper fluid uptake, cooking loss and National Pork Producers Council marbling scores but did not significantly differ from the high pH group (P > 0.05). The low pH group also showed higher Commission International de l’Eclairage L* and b*, drip loss, and shearing forces were significantly different from the high pH group. However, Commission International de l’Eclairage meat colour value (a*) and National Pork Producers Council colour were higher in the high pH group. The content of glutamic acid, threonine, and serine amino acids associated with a good flavour was higher in the high pH group. Also, amino acids associated with a bitter or poor flavour, such as valine, isoleucine, leucine, tyrosine, and histidine, was higher in the high pH group as well. The taste of umami was significantly (P < 0.01) higher in the high pH group. Levels of the nucleotide compounds hypoxanthine and inosine tended to be higher (P < 0.05) in the high pH group, whereas adenosine diphosphate levels were increased in the low pH group (P < 0.05). It is concluded that pH of pork could be a good indicator of pork quality and related to factors influencing pork eating quality. As pH of pork is not only positively associated with physical traits of pork but also closely related to chemical traits of which higher free amino acids and nucleotides enhance pork quality.


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