| 1. |
- Sedzik, Jan, et al.
(författare)
-
Glycans of Myelin Proteins
- 2015
-
Ingår i: Journal of Neuroscience Research. - : Wiley. - 0360-4012 .- 1097-4547. ; 93:1, s. 1-18
-
Forskningsöversikt (refereegranskat)abstract
- Human P0 is the main myelin glycoprotein of the peripheral nervous system. It can bind six different glycans, all linked to Asn(93), the unique glycosylation site. Other myelin glycoproteins, also with a single glycosylation site (PMP22 at Asn(36), MOG at Asn(31)), bind only one glycan. The MAG has 10 glycosylation sites; the glycoprotein OMgp has 11 glycosylation sites. Aside from P0, no comprehensive data are available on other myelin glycoproteins. Here we review and analyze all published data on the physicochemical structure of the glycans linked to P0, PMP22, MOG, and MAG. Most data concern bovine P0, whose glycan moieties have an MW ranging from 1,294.56 Da (GP3) to 2,279.94 Da (GP5). The pI of glycosylated P0 protein varies from pH 9.32 to 9.46. The most charged glycan is MS2 containing three sulfate groups and one glucuronic acid; whereas the least charged one is the BA2 residue. All glycans contain one fucose and one galactose. The most mannose rich are the glycans MS2 and GP4, each of them has four mannoses; OPPE1 contains five N-acetylglucosamines and one sulfated glucuronic acid; GP4 contains one sialic acid. Furthermore, human P0 variants causing both gain and loss of glycosylation have been described and cause peripheral neuropathies with variable clinical severity. In particular, the substitution (TM)-M-95 is a very common in Europe and is associated with a late-onset axonal neuropathy. Although peripheral myelin is made up largely of glycoproteins, mutations altering glycosylation have been described only in P0. This attractive avenue of research requires further study.
|
|
| 2. |
- Sedzik, Jan, et al.
(författare)
-
High-Resolution Structural Model of Porcine P2 Myelin Membrane Protein With Associated Fatty Acid Ligand : Fact or Artifact?
- 2011
-
Ingår i: Journal of Neuroscience Research. - : Wiley. - 0360-4012 .- 1097-4547. ; 89:6, s. 909-920
-
Tidskriftsartikel (refereegranskat)abstract
- Myelin membrane is a biological complex of glial cells origin; it is composed of 25% (w/w) proteins and 75% lipids, and more than 300 proteins are associated with central nervous system myelin (for peripheral nervous system myelin, such data are lacking). Myelin plays an important role in maintaining propagation of nerve signals. To uncover the nature of propagation phenomena, it is essential to study biochemistry of myelin proteins and lipids, myelin composition, and myelin structure. Nearly all myelin proteins are like antigens, causing clinically well-defined devastating diseases; multiple sclerosis and Guillain-Barre syndrome are two of them. In this article, a high-resolution study (1.8 angstrom) of porcine myelin P2 protein is presented. Myelin was purified from porcine intradural spinal roots, which were stored at -80 degrees C for 10 years before myelin and P2 protein were purified (spinal roots were a gift of Prof. Kunio Kitamura, Saitama Medical School). The three-dimensional structural analysis uncovered embedded 18-carbons-long fatty acid. Some speculative interpretation is presented, to uncover how this ligand of fatty acid may form cholesterol ester and stabilize the myelin structure or form simple raft microdomain. Protein crystallography indicates that the ligand may be 18-carbons-long fatty acid. This is unlike previous work with mass spectrometry, in which three ligands were determined. In other protein crystallography-based studies of P2 (bovine), an oleic fatty acid was suggested, but, for recombinant (human) protein, palmitic acid was found. There is no fatty acid ligand in equine P2 protein.
|
|
| 3. |
- Sedzik, Jan, et al.
(författare)
-
Sequence motifs of myelin membrane proteins : Towards the molecular basis of diseases
- 2013
-
Ingår i: Journal of Neuroscience Research. - : Wiley. - 0360-4012 .- 1097-4547. ; 91:4, s. 479-493
-
Tidskriftsartikel (refereegranskat)abstract
- The shortest sequence of amino acids in protein containing functional and structural information is a motif. To understand myelin protein functions, we intensively searched for motifs that can be found in myelin proteins. Some myelin proteins had several different motifs or repetition of the same motif. The most abundant motif found among myelin proteins was a myristoylation motif. Bovine MAG held 11 myristoylation motifs and human myelin basic protein held as many as eight such motifs. PMP22 had the fewest myristoylation motifs, which was only one; rat PMP22 contained no such motifs. Cholesterol recognition/interaction amino-acid consensus (CRAC) motif was not found in myelin basic protein. P2 protein of different species contained only one CRAC motif, except for P2 of horse, which had no such motifs. MAG, MOG, and P0 were very rich in CRAC, three to eight motifs per protein. The analysis of motifs in myelin proteins is expected to provide structural insight and refinement of predicted 3D models for which structures are as yet unknown. Analysis of motifs in mutant proteins associated with neurological diseases uncovered that some motifs disappeared in P0 with mutation found in neurological diseases. There are 2,500 motifs deposited in a databank, but 21 were found in myelin proteins, which is only 1% of the total known motifs. There was great variability in the number of motifs among proteins from different species. The appearance or disappearance of protein motifs after gaining point mutation in the protein related to neurological diseases was very interesting.
|
|
| 4. |
- Maddalo, Gianluca, et al.
(författare)
-
Porcine P2 myelin protein primary structure and bound fatty acids determined by mass spectrometry
- 2010
-
Ingår i: Analytical and Bioanalytical Chemistry. - : Springer Science and Business Media LLC. - 1618-2642 .- 1618-2650. ; 397:5, s. 1903-1910
-
Tidskriftsartikel (refereegranskat)abstract
- Complementary collision-induced/electron capture dissociation Fourier-transform ion cyclotron resonance mass spectrometry was used to fully sequence the protein P2 myelin basic protein. It is an antigenic fatty-acid-binding protein that can induce experimental autoimmune neuritis: an animal model of Guillain-Barre syndrome, a disorder similar in etiology to multiple sclerosis. Neither the primary structure of the porcine variant, nor the fatty acids bound by the protein have been well established to date. A 1.8-angstrom crystal structure shows but a bound ligand could not be unequivocally identified. A protocol for ligand extraction from protein crystals has been developed with subsequent gas chromatography MS analysis allowing determination that oleic, stearic, and palmitic fatty acids are associated with the protein. The results provide unique and general evidence of the utility of mass spectrometry for characterizing proteins from natural sources and generating biochemical information that may facilitate attempts to elucidate the causes for disorders such as demyelination.
|
|
| 5. |
|
|
| 6. |
- Sedzik, Jan
(författare)
-
Fresh water pearls of wisdom on protein crystallization
- 2009
-
Ingår i: Molecules. - : World Scientific Publishing Co.. - 9789812832665 ; , s. 331-344
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- When crystallization experiments are undertaken, there is usually not much to do except miserable waiting. In the following, we have compiled some very insightful comments on crystallization.
|
|
| 7. |
- Sedzik, Jan, et al.
(författare)
-
Gels mimicking antibodies in their selective recognition of proteins and its potential use for protein crystallization
- 2009
-
Ingår i: Molecules: Nucleation, Aggregation and Crystallization: Beyond Medical and Other Implications. - : World Scientific Publishing Co.. - 9789812832665 ; , s. 11-34
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Using a unique molecular-imprinting method we show in this article that human growth hormone, ribonuclease and myoglobin from horse, lysozyme, hemoglobin and albumin can be adsorbed selectively, indicating that the method may be universal or at least applicable to a great number of proteins. A gel with specific adsorption of three model proteins was synthesized in order to demonstrate that the beds can be employed to remove (traces of) several proteins contaminating a sample (“negative purification”). The degree of selective recognition is high, judging from the fact that myoglobin from horse, but not that from whale, was adsorbed onto a column designed to bind specifically the former protein. This selectivity is noteworthy since these two proteins have similar amino acid sequences and 3-D structures. The method for the synthesis of the specific gels involves polymerization of appropriate monomers (for instance, acrylamide and its derivatives) in the presence of the protein to be adsorbed specifically, granulation of the gel formed, packing a column with the gel particles, washing the column to remove the protein, and finally application of the sample for selective adsorption of the protein present during the polymerization of the monomers. The approach resembles that used for entrapment (immobilization) of proteins for affinity chromatography and somewhat like that for molecular imprinting of small molecules, with the distinct difference that the monomer composition is quite different and thereby the binding mechanism. This mechanism is discussed, for instance, in terms of (i) a new classification system for chromatographic beds based on the number of bonds between the solute and the matrix and the strength of each bond, and (ii) “non-specific bonds” (these bonds are often harmful in conventional chromatography, but we have used them to our advantage). In this classification system, the selective recognition is characterized by a large number of weak bonds. Therefore, so-called functional monomers are not used for the preparation of the gels because they are often charged and, accordingly, give rise to strong electrostatic interactions, i.e. the beds behave to some extent as ion exchangers or matrices for hydrophobic interaction chromatography. In most experiments we have used a polyacrylamide gel with large pores to facilitate diffusion of proteins into and out of the gel granules. When used in chromatography, these soft gels (which can be used repeatedly) allow only rather low flow rates. This problem can be overcome by a new approach to preparing the granules. Potential applications of the selective beds are discussed, as well as future improvements. These beds can be synthesized for selective adsorption also of bio-particles, for instance viruses and bacteria, and in the form of monoliths (continuous beds).
|
|
| 8. |
- Sedzik, Jan, et al.
(författare)
-
GLYCOMIX-P0 PROTEIN AND ITS GLYCANS
- 2010
-
Ingår i: Journal of Neurochemistry. - 0022-3042 .- 1471-4159. ; 115, s. 25-25
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
|
|
| 9. |
- Sedzik, Jan, et al.
(författare)
-
Imaging of Myelin Membrane Rafts
- 2009
-
Ingår i: Journal of Neurochemistry. - : Wiley-Blackwell Publishing Inc.. - 0022-3042 .- 1471-4159. ; 110, s. 126-127
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
|
|
| 10. |
- Sedzik, Jan
(författare)
-
Interactive crystallomic
- 2009
-
Ingår i: Molecules: Nucleation, Aggregation and Crystallization: Beyond Medical and Other Implications. - : World Scientific Publishing Co.. - 9789812832665 ; , s. 225-235
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Biologically important molecules have to be crystallized from solution before their atomic structures can be determined. Once their structures have been determined, reliable and fine structural details, which are crucial for structure-based drug design, can be obtained. Crystallization is an important but very poorly understood process. Our inability to produce good quality crystals is a severe limitation of protein crystallography. In this chapter we present rational guidelines which aim to alter our know-how on crystallization from “black magic” into quantitative and affordable science. We have coined a new word, crystallomic, which can be applied to a diverse range of molecules and may intensify research related to crystallogenesis.
|
|
