Four unequally distributed species of hTF differing with regard to iron content are found in plasma: diferric hTF, monoferric N-lobe hTF, monoferric C-lobe hTF, and apohTF (iron-free) ( 1- 3). Sequestration of highly insoluble Fe 3+ by hTF maintains iron in the blood in a non-reactive state, preventing reduction to ferrous iron (Fe 2+) which can catalyze the production of reactive oxygen species via Fenton chemistry. The homologous N- and C-lobes of hTF are divided into two subdomains (N1 and N2, C1 and C2), that fold to form a deep cleft capable of binding a single ferric iron. The transport of iron throughout the body by human serum transferrin (hTF) 1 is central to iron homeostasis. Thus, mutagenesis of charged hTF residues has allowed identification of a number of residues that are critical to formation of and iron release from the hTF/TFR complex. Moreover, mutation of three residues (Asp356, Glu367 and Lys511), whether in the diferric or monoferric C-lobe hTF, significantly affected iron release when in complex with the TFR. In particular, we show that Asp356 in the C-lobe of hTF is essential to the formation of a stable hTF/TFR complex: mutation of Asp356 in the monoferric C-lobe hTF background prevented the formation of the stoichiometric 2:2 (hTF:TFR monomer) complex. Six hTF mutants (R50A, R352A, D356A, E357A, E367A and K511A) competed poorly with biotinylated diferric hTF for binding to TFR. Alanine substitution of eleven charged hTF residues identified by available structures and modeling studies allowed evaluation of the role of each in (1) binding of hTF to the TFR and (2) in TFR-mediated iron release. Identification of the specific residues accounting for the pH-sensitive nanomolar affinity with which hTF binds to TFR throughout the cycle is important to fully understand the iron delivery process. The return of hTF to the blood to continue the iron delivery cycle relies on the maintenance of the interaction between apohTF and the TFR after exposure to endosomal pH (≤ 6.0). Internalization of the complex into an endosome precedes iron removal. Specifically when he made the complicated bits, and left out the more nessessary tools in the package).Efficient delivery of iron is critically dependent on the binding of diferric human serum transferrin (hTF) to its specific receptor (TFR) on the surface of actively dividing cells. There are so many things that could have been done better. (Though, to be honest, the words "FIXED" in the title is a bit. I used a model creator called a "HTF Digiter 1.0" to make Shivers, and was made by Zolrac.
I should maybe start making these for people, see what I can actually make outside the realms of the creatures the maker intended it to be for
I took it into my own art package to add a tail, and minor details I couldn't make through the creator though, but she turned out quite well actually xD Shivers was created using bits of bobs from the maker, and through my own initiative this morning at about 7am, while I waited to leave for the bus at about 8 There's even a tool that doesn't do anything if your HTF char is a cat, bat or dog -_. It's a great art tool, and is well drawn, but by the demons below, the creator was a little dumb. I had attempted Shivers before on it, ages ago, but the same complaint I had back then still holds strongly now.