Crystal structure of a heparin-and integrin-binding segment of human fibronectin

Sharma, Ajeet D.; Askari, Janet A.; Humphries, Martin J.; Jones, E Y; Stuart, D.I.

doi:10.1093/emboj/18.6.1468

Cited by 196 publications

(240 citation statements)

References 75 publications

(94 reference statements)

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“…As shown on Fig. 4B, Fn14 , were derived from P14 -26 with a three-amino acid truncation at the N terminus to discard the non-␤-sheet structure part (38) and had the same inhibition ability as P14 -26 (Fig. 4C).…”

Section: Resultsmentioning

confidence: 98%

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Novel Mycobacteria Antigen 85 Complex Binding Motif on Fibronectin

Kuo

Bell

Hsieh

et al. 2012

Journal of Biological Chemistry

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Section: Resultsmentioning

confidence: 98%

“…The data are mapped onto the structure of Fn14 (Fig. 5B) (38). The 10 amino acids corresponding to P17-26 are a part of the second ␤-sheet and extend into a less structured loop containing adjacent proline residues.…”

Section: Resultsmentioning

confidence: 99%

Novel Mycobacteria Antigen 85 Complex Binding Motif on Fibronectin

Kuo

Bell

Hsieh

et al. 2012

Journal of Biological Chemistry

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“…The binding of heparan sulfate by proteins of known structure can involve a distribution of positively charged side chains on the protein surface that is complementary to the arrangement of the negative sulfate groups along one or both edges of the polymer (64,65). To see whether such a regular arrangement of positive charges would be recognizable in NtACP, the distribution of charges on the molecular surface was calculated (Fig.…”

Section: Discussionmentioning

confidence: 99%

Crystal Structure of the N-terminal Domain of the Group B Streptococcus Alpha C Protein

Auperin

Bolduc

Baron

et al. 2005

Journal of Biological Chemistry

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Group B Streptococcus (GBS) is the leading cause of bacterial pneumonia, sepsis, and meningitis among neonates and an important cause of morbidity among pregnant women and immunocompromised adults. Invasive diseases due to GBS are attributed to the ability of the pathogen to translocate across human epithelial surfaces. The alpha C protein (ACP) has been identified as an invasin that plays a role in internalization and translocation of GBS across epithelial cells. The soluble N-terminal domain of ACP (NtACP) blocks the internalization of GBS. We determined the 1.86-Å resolution crystal structure of NtACP comprising residues Ser 52 through Leu 225 of the full-length ACP. NtACP has two domains, an N-terminal ␤-sandwich and a C-terminal three-helix bundle. Structural and topological alignments reveal that the ␤-sandwich shares structural elements with the type III fibronectin fold (FnIII), but includes structural elaborations that make it unique. We have identified a potential integrin-binding motif consisting of Lys-Thr-Asp 146 , Arg 110 , and Asp 118 . A similar arrangement of charged residues has been described in other invasins. ACP shows a heparin binding activity that requires NtACP. We propose a possible heparin-binding site, including one surface of the three-helix bundle, and nearby portions of the sandwich and repeat domains. We have validated this prediction using assays of the heparin binding and cell-adhesion properties of engineered fragments of ACP. This is the first crystal structure of a member of the highly conserved Gram-positive surface alpha-like protein family, and it will enable the internalization mechanism of GBS to be dissected at the atomic level.Group B Streptococcus (GBS) 1 (Streptococcus agalactiae) remains the leading cause of invasive bacterial diseases in neonates, despite its decline in prevalence during the last decade because of intrapartum chemoprophylatic therapy (1, 2). It is also an important cause of morbidity in pregnant women and non-pregnant adults with underlying medical conditions (3-5). GBS colonizes the human gastrointestinal and genitourinary tracts and may cause chorioamnionitis and urinary tract infection in pregnant women and a range of invasive infections in elderly and immunocompromised adults (1, 6 -8). During labor and delivery, GBS may be transmitted to neonates, causing pneumonia, sepsis, or meningitis. Four to six percent of all neonatal GBS infections result in death (6, 9). In vitro, GBS adheres to (10, 11), internalizes within (12-14), and translocates across (15) intact human epithelial and endothelial cells. Little is known about the bacterial components that allow this pathogen to adhere to and penetrate cellular membranes. Previous studies suggest that surface proteins are significantly involved in the process (11, 16). The surface-expressed GBS alpha C protein (ACP) has been shown to act as an invasin (15). ACP is the prototype of a family of surface-expressed proteins containing long tandem repeats (alpha-like proteins (Alp)). Members of this famil...

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“…All FN domains have a similar ␤-sandwich structure; in domain III-7, the cysteine is the second residue within the "E" strand. Crystal structures of domains III-7-10 (24) and III-12-14 (25) show that the equivalent residue in the E strand is also buried in each of these domains, as does the NMR structure of domains III-1-2 (26). We therefore replaced the second residue of the E strand of each domain with a cysteine.…”

Section: Probing Folded State Of Fn-iii Domains In Cell-stretchedmentioning

confidence: 99%

Probing the Folded State of Fibronectin Type III Domains in Stretched Fibrils by Measuring Buried Cysteine Accessibility

Lemmon

Ohashi

Erickson

2011

Journal of Biological Chemistry

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Fibronectin (FN) is an extracellular matrix protein that is assembled into fibrils by cells during tissue morphogenesis and wound healing. FN matrix fibrils are highly elastic, but the mechanism of elasticity has been debated: it may be achieved by mechanical unfolding of FN-III domains or by a conformational change of the molecule without domain unfolding. Here, we investigate the folded state of FN-III domains in FN fibrils by measuring the accessibility of buried cysteines. Four of the 15 FN-III domains (III-2, -3, -9, and -11) appear to unfold in both stretched fibrils and in solution, suggesting that these domains spontaneously open and close even in the absence of tension. Two FN-III domains (III-6 and -12) appear to unfold only in fibrils and not in solution. These results suggest that domain unfolding can at best contribute partially to the 4-fold extensibility of fibronectin fibrils. Fibronectin (FN)2 is a dimer of a 250-kDa protein that forms insoluble fibrils that are a critical component of the extracellular matrix. It is made up of a series of three domain types connected end-to-end (see Fig. 1A) (1). The N terminus of FN consists of nine FN-I and two FN-II domains, each of which contains an internal disulfide bond. The C terminus of FN consists of three FN-I domains and contains intermolecular disulfides that link the two FN monomers to form the dimer. The central portion of the FN molecule is made up of 15 tandem FN-III domains; these domains each consist of seven ␤-strands folded into a ␤-sandwich structure and contain no internal disulfides (see Fig. 1B). FN in solution adopts a compact conformation in which the second to fourth FN-III domains (III-2-4) of one subunit interact with the 12 th to 14 th FN-III domains (III-12-14) of the other, causing the FN dimer to fold onto itself (see Fig. 1A) (2).FN interacts with both cells and other extracellular matrix proteins. The N-terminal domains contain binding sites for the extracellular matrix proteins collagen and fibrin, whereas the ninth and tenth FN-III domains bind to integrins at the cell surface (3-6). Upon attachment to cells, FN is stretched and assembled into fibrils by cell contraction: matrix assembly is inhibited if cell contractility is inhibited (7) or if tension within the matrix is released (8). Although the exact mechanism of FN fibril formation is still unknown, studies have shown that FN fibrils are stretched to up to 4 times their resting length by cells and are highly elastic structures (9 -12). This elasticity requires cell contraction; disruption of cytoskeletal contraction relaxes stretched fibrils (10).Two different mechanisms have been proposed to explain the elasticity of FN matrix fibrils (see Fig. 1A) (13). One theory contends that the elasticity is a function of FN-III domains unfolding under tension (see Fig. 1A, mechanism 2) (14, 15). These domains contain no internal disulfides and can be mechanically unfolded by atomic force microscopy (16, 17). It is unclear how relevant these atomic force microscopy pulling force...

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Crystal structure of a heparin-and integrin-binding segment of human fibronectin

Cited by 196 publications

References 75 publications

Novel Mycobacteria Antigen 85 Complex Binding Motif on Fibronectin

Novel Mycobacteria Antigen 85 Complex Binding Motif on Fibronectin

Crystal Structure of the N-terminal Domain of the Group B Streptococcus Alpha C Protein

Probing the Folded State of Fibronectin Type III Domains in Stretched Fibrils by Measuring Buried Cysteine Accessibility

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