scholarly journals Role of Positively Charged Amino Acids in the M2DTransmembrane Helix of Ktr/Trk/HKT Type Cation Transporters

Channels ◽  
2007 ◽  
Vol 1 (3) ◽  
pp. 161-171 ◽  
Author(s):  
Naoki Kato ◽  
Masaro Akai ◽  
Lalu Zulkifli ◽  
Nobuyuki Matsuda ◽  
Yasuhiro Kato ◽  
...  
Keyword(s):  
Amino Acids ◽  
Charged Amino Acids ◽  
Cation Transporters ◽  
Positively Charged

scholarly journals The Role of Positively Charged Amino Acids in ATP Recognition by Human P2X1Receptors

2000 ◽  
Vol 275 (38) ◽  
pp. 29361-29367 ◽  
Author(s):  
Steven Ennion ◽  
Sarah Hagan ◽  
Richard J. Evans
Keyword(s):  
Amino Acids ◽  
Charged Amino Acids ◽  
Positively Charged

scholarly journals The role of positively charged amino acids in ATP recognition by human P2X1 receptors.

2000 ◽  
Vol 275 (45) ◽  
pp. 35656
Author(s):  
Steven Ennion ◽  
Sarah Hagan ◽  
Richard J. Evans
Keyword(s):  
Amino Acids ◽  
Charged Amino Acids ◽  
Positively Charged

scholarly journals The role of amino acids in hydroxyapatite mineralization

2016 ◽  
Vol 13 (123) ◽  
pp. 20160462 ◽  
Author(s):  
M. Tavafoghi ◽  
M. Cerruti
Keyword(s):  
Amino Acids ◽  
Critical Role ◽  
Matrix Proteins ◽  
Mineral Density ◽  
Hormone Production ◽  
Charged Amino Acids ◽  
Collagen Mineralization ◽  
Positively Charged

Polar and charged amino acids (AAs) are heavily expressed in non-collagenous proteins (NCPs), and are involved in hydroxyapatite (HA) mineralization in bone. Here, we review what is known on the effect of single AAs on HA precipitation. Negatively charged AAs, such as aspartic acid, glutamic acid (Glu) and phosphoserine are largely expressed in NCPs and play a critical role in controlling HA nucleation and growth. Positively charged ones such as arginine (Arg) or lysine (Lys) are heavily involved in HA nucleation within extracellular matrix proteins such as collagen. Glu, Arg and Lys intake can also increase bone mineral density by stimulating growth hormone production. In vitro studies suggest that the role of AAs in controlling HA precipitation is affected by their mobility. While dissolved AAs are able to inhibit HA precipitation and growth by chelating Ca 2+ and PO 4 3− ions or binding to nuclei of calcium phosphate and preventing their further growth, AAs bound to surfaces can promote HA precipitation by attracting Ca 2+ and PO 4 3− ions and increasing the local supersaturation. Overall, the effect of AAs on HA precipitation is worth being investigated more, especially under conditions closer to the physiological ones, where the presence of other factors such as collagen, mineralization inhibitors, and cells heavily influences HA precipitation. A deeper understanding of the role of AAs in HA mineralization will increase our fundamental knowledge related to bone formation, and could lead to new therapies to improve bone regeneration in damaged tissues or cure pathological diseases caused by excessive mineralization in tissues such as cartilage, blood vessels and cardiac valves.

scholarly journals The Superagonistic Activity of Bovine Thyroid-stimulating Hormone (TSH) and the Human TR1401 TSH Analog Is Determined by Specific Amino Acids in the Hinge Region of the Human TSH Receptor

2009 ◽  
Vol 284 (24) ◽  
pp. 16317-16324 ◽  
Author(s):  
Sandra Mueller ◽  
Gunnar Kleinau ◽  
Mariusz W. Szkudlinski ◽  
Holger Jaeschke ◽  
Gerd Krause ◽  
...  
Keyword(s):  
Amino Acids ◽  
Thyroid Stimulating Hormone ◽  
Hinge Region ◽  
Camp Production ◽  
Glycoprotein Hormone ◽  
Charged Amino Acids ◽  
Bovine Thyroid ◽  
Positively Charged ◽  
Bovine Tsh ◽  
Signaling Activity

Bovine TSH (bTSH) has a higher affinity to the human TSHR (hTSHR) and a higher signaling activity than human TSH (hTSH). The molecular reasons for these phenomena are unknown. Distinct negatively charged residues (Glu297, Glu303, and Asp382) in the hinge region of the hTSHR are known to be important for bTSH binding and signaling. To investigate the potential relevance of these positions for differences between bTSH and hTSH in the interaction to the hTSHR, we determined bTSH- and hTSH-mediated cAMP production of several substitutions at these three hinge residues. To examine specific variations of hTSH, we also investigated the superagonistic hTSH analog TR1401 (TR1401), whose sequence differs from hTSH by four additional positively charged amino acids that are also present in bTSH. To characterize possible interactions between the acidic hTSHR positions Glu297, Glu303, or Asp382 and the additional basic residues of TR1401, we investigated TR1401 binding and signaling properties. Our data reveal increased cAMP signaling of the hTSHR using TR1401 and bTSH compared with hTSH. Whereas Asp382 seems to be important for bTSH- and TR1401-mediated but not for hTSH-mediated signaling, the substitution E297K exhibits a decreased signaling for all three TSH variants. Interestingly, bTSH and TR1401 showed only a slightly different binding pattern. These observations imply that specific residues of the hinge region are mediators of the superagonistic activity of bTSH and TR1401 in contrast to hTSH. Moreover, the simultaneous localization of binding components in the glycoprotein hormone molecule and the receptor hinge region permits important reevaluation of interacting hormone receptor domains.

Sign in / Sign up

Export Citation Format

Share Document