Hemoglobin Brockton [beta 138 (H16) Ala----Pro]: an unstable variant near the C-terminus of the beta-subunits with normal oxygen-binding properties.
Hemoglobin Brockton [beta 138 (H16) Ala----Pro]: an unstable variant near the C-terminus of the beta-subunits with normal oxygen-binding properties.
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血红蛋白 Brockton [β 138 (H16) Ala----Pro]：β 亚基 C 末端附近的不稳定变体，具有正常的氧结合特性。
DOI：
10.1021/bi00420a007
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发表时间：
1988
期刊：
影响因子：
2.9
通讯作者：
Arnone,A
中科院分区：
文献类型：
--
作者：
Moo-Penn,WF;Jue,DL;Johnson,MH;Olsen,KW;Shih,D;Jones,RT;Lux,SE;Rodgers,P;Arnone,A
血红蛋白布罗克顿（{beta}138（H16）Ala {yields} Pro）是与轻度贫血相关的不稳定变体。其电泳迁移率与Hb A相同，且不能与Hb A分离。血液和溶血产物的氧亲和力测量不表明双相氧饱和度，表明变体的功能特性与Hb A的功能特性非常相似。这意味着在位置138处将脯氨酸引入H-螺旋中不会破坏{β}羧基末端二肽处的关键亚基间和亚基内氢键和盐桥，因为这些极性相互作用对于血红蛋白的正常氧结合性质是必不可少的。X射线晶体学数据与这些发现一致，并表明{β}138 Ala {yields} Pro取代的结果几乎完全局限于突变位点附近。不稳定性可能是由于在Pro 138{beta}和瓦尔134{beta}之间不能形成埋置的氢键。
Hemoglobin Brockton ({beta}138 (H16) Ala {yields} Pro) is an unstable variant associated with a mild anemia. It has the same electrophoretic mobility as and cannot be resolved from Hb A. Oxygen affinity measurements of blood and hemolysate do not indicate biphasic oxygen saturation, showing that the functional properties of the variant are very similar to those of Hb A. This implies that the introduction of proline into the H-helix at position 138 does not disrupt the critical inter- and intrasubunit hydrogen bonds and salt bridges at the {beta} carboxyl-terminal dipeptide, since these polar interactions are essential for the normal oxygen-binding properties of hemoglobin. X-ray crystallographic data are consistent with these findings and show that the consequences of the {beta}138 Ala {yields} Pro substitution are almost entirely confined to the immediate vicinity of the mutation site. Instability probably results from the inability of a buried hydrogen bond to form between Pro 138{beta} and Val 134{beta}.