Sequence 377-395(P2), but Not 190-202(P1), Is the Binding Site f
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- 作者：Tatiana P. Ugarova ; Valeryi K. Lishko ; Nataly P. Podolnikova ; Nobuo Okumura ; Sergei M. Merkulov ; Valentin P. Yakubenko ; Vivien C. Yee ; Susan T. Lord ; and Thomas A. Haas
- 刊名：Biochemistry
- 出版年：2003
- 出版时间：August 12, 2003
- 年：2003
- 卷：42
- 期：31
- 页码：9365 - 9373
- 全文大小：407K
- 年卷期：v.42,no.31(August 12, 2003)
- ISSN：1520-4995
文摘
The interaction between the leukocyte integrin 
chars/alpha.gif" BORDER=0>Mchars/beta2.gif" BORDER=0 ALIGN="middle">2 (CD11b/CD18, Mac-1, CR3) and fibrinogenmediates the recruitment of phagocytes during the inflammatory response. Previous studies demonstratedthat peptides P2 and P1, duplicating chars/gamma.gif" BORDER=0 >377-395 and chars/gamma.gif" BORDER=0 >190-202 sequences in the chars/gamma.gif" BORDER=0 >C domain of fibrinogen,respectively, blocked the fibrinogen-binding function of chars/alpha.gif" BORDER=0>Mchars/beta2.gif" BORDER=0 ALIGN="middle">2, implicating these sequences as possiblebinding sites for chars/alpha.gif" BORDER=0>Mchars/beta2.gif" BORDER=0 ALIGN="middle">2. To determine the role of these sequences in integrin binding, recombinant wild-type and mutant chars/gamma.gif" BORDER=0 >C domains were prepared, and their interactions with the chars/alpha.gif" BORDER=0>MI-domain, a ligand recognitiondomain within chars/alpha.gif" BORDER=0>Mchars/beta2.gif" BORDER=0 ALIGN="middle">2, were tested. Deletion of chars/gamma.gif" BORDER=0 >383-411 (P2-C) and chars/gamma.gif" BORDER=0 >377-411 produced chars/gamma.gif" BORDER=0 >C mutantswhich were defective in binding to the chars/alpha.gif" BORDER=0>MI-domain. In contrast, alanine mutations of several residues inP1 did not affect chars/alpha.gif" BORDER=0>MI-domain binding, and simultaneous mutations in P1 and deletion of P2 did notdecrease the binding function of chars/gamma.gif" BORDER=0 >C further. Verifying the significance of P2, inserting P2-C and theentire P2 into the homologous position of the chars/beta2.gif" BORDER=0 ALIGN="middle">C-domain of fibrinogen imparted the higher chars/alpha.gif" BORDER=0>MI-domainbinding ability to the chimeric proteins. To further define the molecular requirements for the P2-C activity,synthetic peptides derived from P2-C and a peptide array covering P2-C have been analyzed, and a minimalrecognition motif was localized to chars/gamma.gif" BORDER=0 >390NRLTIG395. Confirming a critical role of this sequence, the cyclicpeptide NRLTIG retained full activity inherent to P2-C, with Arg and Leu being important residues.Thus, these data demonstrate the essential role of the P2, but not P1, sequence for binding of chars/gamma.gif" BORDER=0 >C by thechars/alpha.gif" BORDER=0>MI-domain and suggest that the adhesive function of P2 depends on the minimal recognition motifNRLTIG.
chars/alpha.gif" BORDER=0>Mchars/beta2.gif" BORDER=0 ALIGN="middle">2 (CD11b/CD18, Mac-1, CR3) and fibrinogenmediates the recruitment of phagocytes during the inflammatory response. Previous studies demonstratedthat peptides P2 and P1, duplicating chars/gamma.gif" BORDER=0 >377-395 and chars/gamma.gif" BORDER=0 >190-202 sequences in the chars/gamma.gif" BORDER=0 >C domain of fibrinogen,respectively, blocked the fibrinogen-binding function of chars/alpha.gif" BORDER=0>Mchars/beta2.gif" BORDER=0 ALIGN="middle">2, implicating these sequences as possiblebinding sites for chars/alpha.gif" BORDER=0>Mchars/beta2.gif" BORDER=0 ALIGN="middle">2. To determine the role of these sequences in integrin binding, recombinant wild-type and mutant chars/gamma.gif" BORDER=0 >C domains were prepared, and their interactions with the chars/alpha.gif" BORDER=0>MI-domain, a ligand recognitiondomain within chars/alpha.gif" BORDER=0>Mchars/beta2.gif" BORDER=0 ALIGN="middle">2, were tested. Deletion of chars/gamma.gif" BORDER=0 >383-411 (P2-C) and chars/gamma.gif" BORDER=0 >377-411 produced chars/gamma.gif" BORDER=0 >C mutantswhich were defective in binding to the chars/alpha.gif" BORDER=0>MI-domain. In contrast, alanine mutations of several residues inP1 did not affect chars/alpha.gif" BORDER=0>MI-domain binding, and simultaneous mutations in P1 and deletion of P2 did notdecrease the binding function of chars/gamma.gif" BORDER=0 >C further. Verifying the significance of P2, inserting P2-C and theentire P2 into the homologous position of the chars/beta2.gif" BORDER=0 ALIGN="middle">C-domain of fibrinogen imparted the higher chars/alpha.gif" BORDER=0>MI-domainbinding ability to the chimeric proteins. To further define the molecular requirements for the P2-C activity,synthetic peptides derived from P2-C and a peptide array covering P2-C have been analyzed, and a minimalrecognition motif was localized to chars/gamma.gif" BORDER=0 >390NRLTIG395. Confirming a critical role of this sequence, the cyclicpeptide NRLTIG retained full activity inherent to P2-C, with Arg and Leu being important residues.Thus, these data demonstrate the essential role of the P2, but not P1, sequence for binding of chars/gamma.gif" BORDER=0 >C by thechars/alpha.gif" BORDER=0>MI-domain and suggest that the adhesive function of P2 depends on the minimal recognition motifNRLTIG.