From the article,\" Elephantids are a particularly good model system to investig

Question

From the article," Elephantids are a particularly good model system to investigate the effects of temperature on Hb structure-function relationships as they possess both warm- and members. Specifically, the group evolved in warm subtemperate climates, where extant Asian and African lineages are still found, with the ancestors of the extinct woolly mammoth (Mammuthus primigenius) abruptly invading high-latitude environments of Eurasia near the start of the Pleistocene ice ages some 1.2-2.0 million years ago.Consistent with this environmental diaspora, the functional properties of woolly mammoth Hb were found to differ substantially from those of Asian elephant Hb, with the most notable change being a ant reduction in the overall AH of th rotein in the presence of sInterestingly, this functional shift comes about despite atu the fact that the primary sequences of Asian elephant Hb differ from those of the mammoth at only one position in the -globin chain (KSN) and at three positions(T12A, A865, and E101Q) in the -type globin chain, respectively (Table 1) Of these latter residues, /612Ala of the mammoth protein is near the 23-bisphosphoglycerate (BPG) binding cleft, /d86Ser is in the heme pocket, and /6101 Gln is located between 99Asp and 102Asn of the same chain in the intersubunit !(/d):interface, which are all critical to the function of Hb." ccurri 5a. Why is the amino acid change near the BPG binding site important to consider in determining how mammoth Hb functions relative to Asian elephant Hb? Note: Hb is the abbreviation for hemoglobin. 5b. In the experimental description, the authors state that any sample of hemoglobin (Hb) that was determined to have concentration of met-Hb (Hb with Fe(III) bound) greater than 5% was not used for 02 biding studies. Briefly explain why they rejected these samples for study?

Explanation / Answer

Ans 5a) In this it was found that the significant difference in HB is caused due to position of the -globin chain(K5N) and at other three positions which are in -type globin chain. In case of mammoth, the /ð12 Ala is present near the BPG binding cleft and is one the critical aspect. It is one of the considerations on determining the Hb function between mammoth an Asian elephant i.e amino acid change near the BPG binding site is a determining factor. The overall change in the enthalpy in the mammoth protein is significantly reduced in case of a mammoth when there is an allosteric effector molecule present. The amino acid change near BPG is considered important as it leads to reduced enthalpy due to presence of allosteric molecules which hinders the effective movement. The changes are as such that it helps the woolly mammoth to get more resistance and survive as the temperature reduces.

Ans 5b) The samples with met-Hb (Hb with Fe(III) bound) greater than 5% was rejected for 02 binding studies as it led to allosteric interference and led to restriction in the study of Hb pattern.

Related Questions

Navigate

• Browse (All)
• Browse F
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.