PDBsum entry 2go0

Protein binding

PDB id: 2go0

Contents

Protein chain

137 a.a. *

* Residue conservation analysis

PDB id:

2go0

Name:

Protein binding

Title:

Nmr solution structure of human pancreatitis-associated protein

Structure:

Regenerating islet-derived protein 3 alpha. Chain: a. Fragment: residues 1-137. Synonym: reg iii-alpha, pancreatitis-associated protein 1. Engineered: yes

Source:

Homo sapiens. Human. Organism_taxid: 9606. Expressed in: escherichia coli. Expression_system_taxid: 562

NMR struc:

20 models

Authors:

C.P.Chen,M.R.Ho,Y.C.Lou

Key ref:

M.R.Ho et al. (2006). Human pancreatitis-associated protein forms fibrillar aggregates with a native-like conformation. J Biol Chem, 281, 33566-33576. PubMed id: 16963458 DOI: 10.1074/jbc.M604513200

Date:

12-Apr-06 Release date: 12-Sep-06

Protein chain

Q06141  (REG3A_HUMAN) -  Regenerating islet-derived protein 3-alpha from Homo sapiens

Seq: 175 a.a.

Struc: 137 a.a.

DOI no: 10.1074/jbc.M604513200

J Biol Chem 281:33566-33576 (2006)

PubMed id: 16963458

Human pancreatitis-associated protein forms fibrillar aggregates with a native-like conformation.

M.R.Ho, Y.C.Lou, W.C.Lin, P.C.Lyu, W.N.Huang, C.Chen.

ABSTRACT

Human pancreatitis-associated protein was identified in pathognomonic lesions of Alzheimer disease, a disease characterized by the presence of filamentous protein aggregates. Here, we showed that at physiological pH, human pancreatitis-associated protein forms non-Congo Red-binding, proteinase K-resistant fibrillar aggregates with diameters from 6 up to as large as 68 nm. Interestingly, circular dichroism and Fourier transform infrared spectra showed that, unlike typical amyloid fibrils, which have a cross-beta-sheet structure, these aggregates have a very similar secondary structure to that of the native protein, which is composed of two alpha-helices and eight beta-strands, as determined by NMR techniques. Surface structure analysis showed that the positively charged and negatively charged residues were clustered on opposite sides, and strong electrostatic interactions between molecules were therefore very likely, which was confirmed by cross-linking experiments. In addition, several hydrophobic residues were found to constitute a continuous hydrophobic surface. These results and protein aggregation prediction using the TANGO algorithm led us to synthesize peptide Thr(84) to Ser(116), which, very interestingly, was found to form amyloid-like fibrils with a cross-beta structure. Thus, our data suggested that human pancreatitis-associated protein fibrillization is initiated by protein aggregation primarily because of electrostatic interactions, and the loop from residues 84 to 116 may play an important role in the formation of fibrillar aggregates with a native-like conformation.

Selected figure(s)

Figure 2.
FIGURE 2. hPAP retains a native-like conformation when assembled into fibrillar aggregates. A, CR binding assay. The dashed line shows the signal for CR alone (15 µM), and the solid line shows the absorption of CR mixed with hPAP fibrillar aggregates (10 µM). B, FTIR spectra of soluble hPAP (solid line) and fibrillar hPAP (dashed line) at pH 7.0. The inset depicts the deconvolution of the signals in the amide I region.

Figure 7.
FIGURE 7. Comparison of hPAP and hLIT. A, sequence alignment of hPAP and hLIT (identity, 47%). The secondary structures of hPAP are shown, and the trypsin cleavage site is indicated by a red arrow. Residue numbers for hPAP are shown above the sequences, and those for hLIT are below the sequences. The electrostatic potentials of the molecule surface of hPAP (B) and hLIT (D) are shown with a similar orientation. Negative potentials are colored red, and positive potentials are blue. The hydrophobic surfaces of hPAP (C) and hLIT (E) are also shown with a similar orientation. The protein surface is shown in green, and exposed hydrophobic residues (Ala, Val, Leu, Ile, Pro, Phe, Tyr, and Trp) are in yellow.

The above figures are reprinted by permission from the ASBMB: J Biol Chem (2006, 281, 33566-33576) copyright 2006.

Figures were selected by an automated process.