Identification of functionally important residues of the epidermal growth factor-2 domain of factor IX by alanine-scanning mutagenesis

Residues Asn89-Gly93 are critical for binding factor VIIIa

Yu Jia Chang, Hua Lin Wu, Nobuko Hamaguchi, Ya Chu Hsu, Shu Wha Lin

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31 Citations (Scopus)

Abstract

This paper describes the consequences of alanine-scanning mutagenesis on 28 positions of the second epidermal growth factor (EGF-2) domain of factor IX. We identified four positions of Gln97, Phe98, Tyr115, and Leu117 that are critical for secretion of factor IX. Of the remaining mutations, 4 mutants (V86A, E113A, K122A, and S123A) are as active as wild-type factor IX (IXwt); 16 (D85A, K100A, N101A, D104A, N105A, R116A, E119A, T87A, 190A, K91A, R94A, E96A, S102A, K106A, T112A, and N120A) retain reduced but detectable activity, and 4 (N89A, N92A, G93A, and V107A) are nearly inert in the clotting assay. Both factor XIa and the factor VIIa-tissue factor complex effectively catalyzed the activation of these mutants except N89A. The mutant V107A failed to form the factor tenase complex with factor VIIIa because of a 35-fold increase in Kd. The mutants N89A and N92A did not compete with factor IXwt for factor VIIIa binding, and G93A exhibited a 6-fold increase in Ki values in the competitive binding assay. It appears that mutations at these positions have significantly affected the interaction between factor IX and factor VIIIa, although other mutations had little effect on the binding of factor IX to factor VIIIa. Mutations in two regions, Thr87-Gly93 and Asn101-Val107, significantly increased the Km value of factor IXa (2-10-fold) in cleavage of factor X in the absence of factor VIIIa. In the presence of factor VIIIa, the catalytic efficiency of each mutant toward factor X paralleled its clotting activity. Briefly, we propose two relatively distinctive functions of factor IX for two adjacent regions in the EGF-2 domain; the first loop region (residues 89-94) is involved with the binding of its cofactor, factor VIIIa, and the third loop with connected β-sheets (residues 102-108) is involved in the proper binding to the substrate, factor X.

Original languageEnglish
Pages (from-to)25393-25399
Number of pages7
JournalJournal of Biological Chemistry
Volume277
Issue number28
DOIs
Publication statusPublished - Jul 12 2002
Externally publishedYes

Fingerprint

Factor VIIIa
Mutagenesis
Factor IX
Epidermal Growth Factor
Alanine
Scanning
Factor X
Mutation
cancer procoagulant
Assays
Factor XIa
Factor IXa
Factor VIIa
Competitive Binding
Thromboplastin
Chemical activation

ASJC Scopus subject areas

  • Biochemistry

Cite this

Identification of functionally important residues of the epidermal growth factor-2 domain of factor IX by alanine-scanning mutagenesis : Residues Asn89-Gly93 are critical for binding factor VIIIa. / Chang, Yu Jia; Wu, Hua Lin; Hamaguchi, Nobuko; Hsu, Ya Chu; Lin, Shu Wha.

In: Journal of Biological Chemistry, Vol. 277, No. 28, 12.07.2002, p. 25393-25399.

Research output: Contribution to journalArticle

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title = "Identification of functionally important residues of the epidermal growth factor-2 domain of factor IX by alanine-scanning mutagenesis: Residues Asn89-Gly93 are critical for binding factor VIIIa",
abstract = "This paper describes the consequences of alanine-scanning mutagenesis on 28 positions of the second epidermal growth factor (EGF-2) domain of factor IX. We identified four positions of Gln97, Phe98, Tyr115, and Leu117 that are critical for secretion of factor IX. Of the remaining mutations, 4 mutants (V86A, E113A, K122A, and S123A) are as active as wild-type factor IX (IXwt); 16 (D85A, K100A, N101A, D104A, N105A, R116A, E119A, T87A, 190A, K91A, R94A, E96A, S102A, K106A, T112A, and N120A) retain reduced but detectable activity, and 4 (N89A, N92A, G93A, and V107A) are nearly inert in the clotting assay. Both factor XIa and the factor VIIa-tissue factor complex effectively catalyzed the activation of these mutants except N89A. The mutant V107A failed to form the factor tenase complex with factor VIIIa because of a 35-fold increase in Kd. The mutants N89A and N92A did not compete with factor IXwt for factor VIIIa binding, and G93A exhibited a 6-fold increase in Ki values in the competitive binding assay. It appears that mutations at these positions have significantly affected the interaction between factor IX and factor VIIIa, although other mutations had little effect on the binding of factor IX to factor VIIIa. Mutations in two regions, Thr87-Gly93 and Asn101-Val107, significantly increased the Km value of factor IXa (2-10-fold) in cleavage of factor X in the absence of factor VIIIa. In the presence of factor VIIIa, the catalytic efficiency of each mutant toward factor X paralleled its clotting activity. Briefly, we propose two relatively distinctive functions of factor IX for two adjacent regions in the EGF-2 domain; the first loop region (residues 89-94) is involved with the binding of its cofactor, factor VIIIa, and the third loop with connected β-sheets (residues 102-108) is involved in the proper binding to the substrate, factor X.",
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T1 - Identification of functionally important residues of the epidermal growth factor-2 domain of factor IX by alanine-scanning mutagenesis

T2 - Residues Asn89-Gly93 are critical for binding factor VIIIa

AU - Chang, Yu Jia

AU - Wu, Hua Lin

AU - Hamaguchi, Nobuko

AU - Hsu, Ya Chu

AU - Lin, Shu Wha

PY - 2002/7/12

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N2 - This paper describes the consequences of alanine-scanning mutagenesis on 28 positions of the second epidermal growth factor (EGF-2) domain of factor IX. We identified four positions of Gln97, Phe98, Tyr115, and Leu117 that are critical for secretion of factor IX. Of the remaining mutations, 4 mutants (V86A, E113A, K122A, and S123A) are as active as wild-type factor IX (IXwt); 16 (D85A, K100A, N101A, D104A, N105A, R116A, E119A, T87A, 190A, K91A, R94A, E96A, S102A, K106A, T112A, and N120A) retain reduced but detectable activity, and 4 (N89A, N92A, G93A, and V107A) are nearly inert in the clotting assay. Both factor XIa and the factor VIIa-tissue factor complex effectively catalyzed the activation of these mutants except N89A. The mutant V107A failed to form the factor tenase complex with factor VIIIa because of a 35-fold increase in Kd. The mutants N89A and N92A did not compete with factor IXwt for factor VIIIa binding, and G93A exhibited a 6-fold increase in Ki values in the competitive binding assay. It appears that mutations at these positions have significantly affected the interaction between factor IX and factor VIIIa, although other mutations had little effect on the binding of factor IX to factor VIIIa. Mutations in two regions, Thr87-Gly93 and Asn101-Val107, significantly increased the Km value of factor IXa (2-10-fold) in cleavage of factor X in the absence of factor VIIIa. In the presence of factor VIIIa, the catalytic efficiency of each mutant toward factor X paralleled its clotting activity. Briefly, we propose two relatively distinctive functions of factor IX for two adjacent regions in the EGF-2 domain; the first loop region (residues 89-94) is involved with the binding of its cofactor, factor VIIIa, and the third loop with connected β-sheets (residues 102-108) is involved in the proper binding to the substrate, factor X.

AB - This paper describes the consequences of alanine-scanning mutagenesis on 28 positions of the second epidermal growth factor (EGF-2) domain of factor IX. We identified four positions of Gln97, Phe98, Tyr115, and Leu117 that are critical for secretion of factor IX. Of the remaining mutations, 4 mutants (V86A, E113A, K122A, and S123A) are as active as wild-type factor IX (IXwt); 16 (D85A, K100A, N101A, D104A, N105A, R116A, E119A, T87A, 190A, K91A, R94A, E96A, S102A, K106A, T112A, and N120A) retain reduced but detectable activity, and 4 (N89A, N92A, G93A, and V107A) are nearly inert in the clotting assay. Both factor XIa and the factor VIIa-tissue factor complex effectively catalyzed the activation of these mutants except N89A. The mutant V107A failed to form the factor tenase complex with factor VIIIa because of a 35-fold increase in Kd. The mutants N89A and N92A did not compete with factor IXwt for factor VIIIa binding, and G93A exhibited a 6-fold increase in Ki values in the competitive binding assay. It appears that mutations at these positions have significantly affected the interaction between factor IX and factor VIIIa, although other mutations had little effect on the binding of factor IX to factor VIIIa. Mutations in two regions, Thr87-Gly93 and Asn101-Val107, significantly increased the Km value of factor IXa (2-10-fold) in cleavage of factor X in the absence of factor VIIIa. In the presence of factor VIIIa, the catalytic efficiency of each mutant toward factor X paralleled its clotting activity. Briefly, we propose two relatively distinctive functions of factor IX for two adjacent regions in the EGF-2 domain; the first loop region (residues 89-94) is involved with the binding of its cofactor, factor VIIIa, and the third loop with connected β-sheets (residues 102-108) is involved in the proper binding to the substrate, factor X.

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