Triple‐helical peptides: An approach to collagen conformation, stability, and self‐association

Brodsky, Barbara; Thiagarajan, Geetha; Madhan, Balaraman; Kar, Karunakar

doi:10.1002/bip.20958

Cited by 167 publications

(136 citation statements)

References 51 publications

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“…Perhaps ␣1(V)436 -447 fTHP might form small soluble aggregates that impede and complicate hydrolysis by MMP-12 but not the hydrolysis by gelatinases. Higher order self-association has been reported for some THPs (93). Alternatively MMP-12 might be more sensitive to product inhibition.…”

Section: ␣1(v) Thp Protection Of Mmp-12(e219a) Frommentioning

confidence: 89%

MMP-12 Catalytic Domain Recognizes Triple Helical Peptide Models of Collagen V with Exosites and High Activity

Bhaskaran

Palmier

Lauer‐Fields

et al. 2008

Journal of Biological Chemistry

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Collagens are principal constituents of connective tissues. They are hydrolyzed during development, wound repair, and remodeling of the extracellular matrix. Dysregulated collagenolysis is active in inflammatory diseases such as atherosclerosis, cancer, rheumatoid arthritis, periodontitis, and liver and kidney pathologies. Matrix metalloproteinases (MMPs) 3 play key roles in these processes (1-3). Mutagenesis has established the importance of the V-B loop (joining ␤-strand V and helix B) in collagenolysis by MMP-1 (4). Residues at the C-terminal end of this loop in MMP-8 were also implicated in collagenolysis (5) and triple helical peptidase activity (6).Binding of an inactivated MMP-1 to an intact collagen fibril likely unwinds the triple helix at the cleavage site to provide access for an active MMP-1 catalytic domain to hydrolyze individual chains (7). The direction of collagen triple helices at the active site is unknown, but the orientation can be hypothesized to be the same as in linear peptide substrates that run antiparallel to ␤-strand IV (8, 9). Single chain peptides from the ␣1 chain of type I/III collagens were soaked into crystals of MMP-12 and MMP-8 catalytic domains, and snapshots of bound hydrolysis products were obtained (8).However, neither crystallography nor NMR data representative of interactions with collagen have been reported because of technical limitations. More generally, structural studies of complexes of enzymes with their substrates have been rare presumably because of catalytic turnover and affinities lower than those for transition state analogues. Several biologically active, self-assembling triple helical peptide (THP) mimics of collagens have been developed. These THPs have facilitated numerous biochemical and cell biological studies otherwise infeasible with insoluble, intact collagen fibrils. THPs are successful in reproducing the cleavage sites of MMPs in collagens I, II, III, V, and XI and in reproducing rate dependences on intact triple helical structure (10, 11). Fluorogenic labeling of THPs has facilitated quantitative comparisons of the triple helical peptidase activities of a variety of MMPs in solution and in cell culture assay (6,11,12). The affinities of MMP catalytic domains for triple helices range from 1 to 80 M (6, 11-13). Collagenolysis involves several MMP functions that include initial nonspecific binding and orientation of collagen fibrils (14, 15), manipulation of collagen fibrils with the C-terminal hemopexin domain (16) and catalytic domain (7), unwinding of triple helices within fibrils, and ensuing hydrolysis of single chains from the melted triple helix (7). THPs are not suitable for modeling the initial binding, orientation, and manipulation of full-length collagen assembled into large, insoluble fibrils (6, 11). They are too small to participate in these higher order events (7). Nonetheless THPs have proven themselves to be outstanding substrates for detailed characterization of the triple helical peptidase activities of MMPs and other metalloprotein...

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Section: ␣1(v) Thp Protection Of Mmp-12(e219a) Frommentioning

confidence: 89%

MMP-12 Catalytic Domain Recognizes Triple Helical Peptide Models of Collagen V with Exosites and High Activity

Bhaskaran

Palmier

Lauer‐Fields

et al. 2008

Journal of Biological Chemistry

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“…Similarly, a model for fibrous collagen with three left-handed polyproline type II (PPII) helices forming a right-handed supercoil was proposed (26) and then observed structurally (27). However, the formation of a unified hybrid structure composed of both α-and PPII helices was unknown.…”

Section: Discussionmentioning

confidence: 99%

Elongated fibrillar structure of a streptococcal adhesin assembled by the high-affinity association of α- and PPII-helices

Larson

Rajashankar

Patel

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

175

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Streptococcus mutans antigen I/II (AgI/II) is a cell surface-localized protein adhesin that interacts with salivary components within the salivary pellicle. AgI/II contributes to virulence and has been studied as an immunological and structural target, but a fundamental understanding of its underlying architecture has been lacking. Here we report a high-resolution (1.8 Å) crystal structure of the A 3 VP 1 fragment of S. mutans AgI/II that demonstrates a unique fibrillar form (155 Å) through the interaction of two noncontiguous regions in the primary sequence. The A 3 repeat of the alanine-rich domain adopts an extended α-helix that intertwines with the P 1 repeat polyproline type II (PPII) helix to form a highly extended stalk-like structure heretofore unseen in prokaryotic or eukaryotic protein structures. Velocity sedimentation studies indicate that fulllength AgI/II that contains three A/P repeats extends over 50 nanometers in length. Isothermal titration calorimetry revealed that the high-affinity association between the A 3 and P 1 helices is enthalpically driven. Two distinct binding sites on AgI/II to the host receptor salivary agglutinin (SAG) were identified by surface plasmon resonance (SPR). The current crystal structure reveals that AgI/II family proteins are extended fibrillar structures with the number of alanine-and proline-rich repeats determining their length.bacterial adhesion | dental caries | Streptococcus | x-ray crystallography | fibrous proteins S treptococcus mutans is the causative agent of human dental caries (1) and its protein adhesin antigen I/II (AgI/II) is a known target of protective immunity (2). AgI/II family molecules are expressed by numerous oral streptococci (3) and homologs have also been identified in the invasive pathogens Streptococcus pyogenes and Streptococcus agalactiae (4) (Fig. S1). In addition to mediating adhesion to the tooth surface (5), AgI/II influences biofilm formation (6), promotes collagen-dependent bacterial invasion of dentin (7), and mediates adherence to human epithelial cells (8). Elimination of AgI/II results in decreased virulence (9), but despite three decades of study, a mechanistic understanding of the functional properties of the molecule has been stymied by a lack of understanding of its structure.Originally identified as AgI/II (10) (also called P1, PAc, or SpaP), members of this protein family contain between 1310 and 1653 amino acids (aa) beginning with an amino-terminal signal motif that directs secretion, followed by the A, V, and P regions (Fig. 1A). The A region typically consists of 3-4 alanine-rich repeats (82 residues each) with 23-30% alanine content. The P region has 3-4 proline-rich repeats (39 residues each) with ∼35% proline content. Nested between the A and P repeats is a segment commonly referred to as the V or variable region, which contains within it a stretch of ∼100 amino acids where most of the sequence variation among S. mutans AgI/II molecules is clustered (11). The crystal structure of the V region adopts a globular β-s...

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“…Indeed, 10% of native collagen sequences consist of the GPO triplet (42). Peptides containing GPO or GPP repeats also adopt a collagen-like triple helix (9). Using such model peptides, we showed that YadA binds as tightly to a hydroxyproline-rich collagenous triple helix as to native collagen (30).…”

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confidence: 97%

First Analysis of a Bacterial Collagen-Binding Protein with Collagen Toolkits: Promiscuous Binding of YadA to Collagens May Explain How YadA Interferes with Host Processes

et al. 2010

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The Yersinia adhesin YadA mediates the adhesion of the human enteropathogen Yersinia enterocolitica to collagens and other components of the extracellular matrix. Though YadA has been proposed to bind to a specific site in collagens, the exact binding determinants for YadA in native collagen have not previously been elucidated. We investigated the binding of YadA to collagen Toolkits, which are libraries of triple-helical peptides spanning the sequences of type II and III human collagens. YadA bound to many of them, in particular to peptides rich in hydroxyproline but with few charged residues. We were able to block the binding of YadA to collagen type IV with the triple-helical peptide (Pro-Hyp-Gly) 10 , suggesting that the same site in YadA binds to triple-helical regions in network-forming collagens as well. We showed that a single Gly-Pro-Hyp triplet in a triple-helical peptide was sufficient to support YadA binding, but more than six triplets were required to form a tight YadA binding site. This is significantly longer than the case for eukaryotic collagenbinding proteins. YadA-expressing bacteria bound promiscuously to Toolkit peptides. Promiscuous binding could be advantageous for pathogenicity in Y. enterocolitica and, indeed, for other pathogenic bacteria. Many of the tightly binding peptides are also targets for eukaryotic collagen-binding proteins, and YadA was able to inhibit the interaction between selected Toolkit peptides and platelets. This leads to the intriguing possibility that YadA may interfere in vivo with host processes mediated by endogenous collagen-binding proteins.

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Triple‐helical peptides: An approach to collagen conformation, stability, and self‐association

Cited by 167 publications

References 51 publications

MMP-12 Catalytic Domain Recognizes Triple Helical Peptide Models of Collagen V with Exosites and High Activity

MMP-12 Catalytic Domain Recognizes Triple Helical Peptide Models of Collagen V with Exosites and High Activity

Elongated fibrillar structure of a streptococcal adhesin assembled by the high-affinity association of α- and PPII-helices

First Analysis of a Bacterial Collagen-Binding Protein with Collagen Toolkits: Promiscuous Binding of YadA to Collagens May Explain How YadA Interferes with Host Processes

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