Abstract
Alpha hemoglobin stabilizing protein (AHSP) reversibly binds nascent α globin to maintain its native structure and facilitate its incorporation into hemoglobin A. Previous studies indicate that some naturally occurring human α globin mutations may destabilize the protein by inhibiting its interactions with AHSP. However, these mutations could also affect hemoglobin A production through AHSP-independent effects, including reduced binding to β globin. We analyzed 6 human α globin variants with altered AHSP contact surfaces. Alpha globin amino acid substitutions H103Y, H103R, F117S, and P119S impaired interactions with both AHSP and β globin. These mutations are destabilizing in biochemical assays and are associated with microcytosis and anemia in humans. By contrast, K99E and K99N α globins bind β globin normally but exhibit attenuated binding to AHSP. These mutations impair protein folding and expression in vitro and appear to be mildly destabilizing in vivo. In Escherichia coli and erythroid cells, α globin K99E stability is rescued on coexpression with AHSP mutants in which binding to the abnormal globin chain is restored. Our results better define the biochemical properties of some α globin variants and support the hypothesis that AHSP promotes α globin chain stability during human erythropoiesis.
| Original language | English |
|---|---|
| Pages (from-to) | 5961-5969 |
| Number of pages | 9 |
| Journal | Blood |
| Volume | 113 |
| Issue number | 23 |
| DOIs | |
| Publication status | Published - 2009 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Hematology
- Biochemistry
- Cell Biology
- Immunology
Cite this
Analysis of human α globin gene mutations that impair binding to the α hemoglobin stabilizing protein. / Yu, Xiang; Mollan, Todd L.; Butler, Andrew; Gow, Andrew J.; Olson, John S.; Weiss, Mitchell J.
In: Blood, Vol. 113, No. 23, 2009, p. 5961-5969.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Analysis of human α globin gene mutations that impair binding to the α hemoglobin stabilizing protein
AU - Yu, Xiang
AU - Mollan, Todd L.
AU - Butler, Andrew
AU - Gow, Andrew J.
AU - Olson, John S.
AU - Weiss, Mitchell J.
PY - 2009
Y1 - 2009
N2 - Alpha hemoglobin stabilizing protein (AHSP) reversibly binds nascent α globin to maintain its native structure and facilitate its incorporation into hemoglobin A. Previous studies indicate that some naturally occurring human α globin mutations may destabilize the protein by inhibiting its interactions with AHSP. However, these mutations could also affect hemoglobin A production through AHSP-independent effects, including reduced binding to β globin. We analyzed 6 human α globin variants with altered AHSP contact surfaces. Alpha globin amino acid substitutions H103Y, H103R, F117S, and P119S impaired interactions with both AHSP and β globin. These mutations are destabilizing in biochemical assays and are associated with microcytosis and anemia in humans. By contrast, K99E and K99N α globins bind β globin normally but exhibit attenuated binding to AHSP. These mutations impair protein folding and expression in vitro and appear to be mildly destabilizing in vivo. In Escherichia coli and erythroid cells, α globin K99E stability is rescued on coexpression with AHSP mutants in which binding to the abnormal globin chain is restored. Our results better define the biochemical properties of some α globin variants and support the hypothesis that AHSP promotes α globin chain stability during human erythropoiesis.
AB - Alpha hemoglobin stabilizing protein (AHSP) reversibly binds nascent α globin to maintain its native structure and facilitate its incorporation into hemoglobin A. Previous studies indicate that some naturally occurring human α globin mutations may destabilize the protein by inhibiting its interactions with AHSP. However, these mutations could also affect hemoglobin A production through AHSP-independent effects, including reduced binding to β globin. We analyzed 6 human α globin variants with altered AHSP contact surfaces. Alpha globin amino acid substitutions H103Y, H103R, F117S, and P119S impaired interactions with both AHSP and β globin. These mutations are destabilizing in biochemical assays and are associated with microcytosis and anemia in humans. By contrast, K99E and K99N α globins bind β globin normally but exhibit attenuated binding to AHSP. These mutations impair protein folding and expression in vitro and appear to be mildly destabilizing in vivo. In Escherichia coli and erythroid cells, α globin K99E stability is rescued on coexpression with AHSP mutants in which binding to the abnormal globin chain is restored. Our results better define the biochemical properties of some α globin variants and support the hypothesis that AHSP promotes α globin chain stability during human erythropoiesis.
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U2 - 10.1182/blood-2008-12-196030
DO - 10.1182/blood-2008-12-196030
M3 - Article
VL - 113
SP - 5961
EP - 5969
JO - Blood
JF - Blood
SN - 0006-4971
IS - 23
ER -