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Protein & Peptide Letters, Volume 9, No. 6, 2002

 

Contents

 

Characterization of Rhodamine Conjugated Agiotensin II Peptide: Synthesis, Analysis and Receptor Binding and Internalization. Pp.465-476

Satya P. Yadav, Sadashiv Karnick, Wei-Zhen Shen, and Jingli Zhang

[Abstract]

 

Virus-Cell Fusion Inhibitory Activity of Novel Analogue Peptides Based on the HP (2-20) Derived from N-Terminus of Helicobacter Pylori Ribosomal Protein L1 Pp.477-486

Eun-Rhan Woo, Dong Gun Lee, Young-Su Chang, Yoonkyung Park and Kyung-Soo Hahm

[Abstract]

 

Structure-Antibacterial Activity Relationship of Cecropin A Derivatives Pp.487-493

Song Yub Shin, Keun Woo Lee, Yangmee Kim, Jae II Kim, Kyung-Soo Hahm and Shin-Won Kang

[Abstract]

 

A Model for the Cytoplasmic Domain of the Influenza A Virus M2 Channel by Analogy to the HIV-1 Vpu Protein Pp.495-502

José W. Saldanha, Peter E. Czabotar, Alan J. Hay and William R. Taylor

[Abstract]

 

Selective Precipitation of Haptoglobin and a2-Macroglobulin from Human Serum Using Alocasia macrorhiza Tuber Protein Pp.503-510

B. Shivananda Nayak, N. Jagadish Ulloor and B. Shivaraj

[Abstract]

 

Biochemical Characterization of Apoptotic Cleavage of KH-Type Splicing Regulatory Protein (KSRP)/Far Upstream Element-Binding Protein 2 (FBP2) Pp.511-519

Heeyoung Seok, Jinsun Cho, Minseok Cheon and II-Seon Park

[Abstract]

 

Acyl-Gelatins for Cell-Hybrid Biomaterials: Preparation of Gelatins with High Melting Point and Affinity for Hydrophobic Surfaces Pp.521-528

Keiichi Miyamoto, Hiroko Chinzei and Takashi Komai

[Abstract]

 

Synthesis of Alkyl and Aryl Esters of N-Protected b-Homoamino Acids from N-Protected a-Aminodiazoketones Pp.529-532

G. R. Vasanthakumar, H. N. Gopi and V. V. Suresh Babu

[Abstract]

 

Antibiotic Properties of Novel Synthetic Temporin A Analogs and a Cecropin A-Temporin A Hybrid Peptide Pp.533-543

David Wade, Jan-Ingmar Flock, Charlotta Edlund, Ingegerd Löfving-Arvholm,Matti Sällberg, Tomas Bergman, Angela Silveira, Cecille Unson,Louise Rollins-Smith, Jerzy Silberring, Malcom Richardson, Pentti Kuusela and Hilkka Lankinen

[Abstract]

 

A Direct Continuous pH-Spectrophotometric Assay for Arginine Kinase Activity Pp.545-552

Yu Z., Pan J. and Zhou H.M.

[Abstract]

 

Crystallization Report

 

Purification, Crystallization and Preliminary X-Ray Studies of Human Augmenter of Liver Regeneration Pp.553-556

Chao-Neng Ji, Zai-Long Cai, Gen-Tao Cao, Gang Yin, Bing-Hua Jiao Tao Jiang, Guang Shu, Ji-Fang Mao, Yi Xie, and Yu-Min Mao

[Abstract]

 

Abstracts

 

[Back to top] Characterization of Rhodamine Conjugated Agiotensin II Peptide: Synthesis, Analysis and Receptor Binding and Internalization.

Satya P. Yadav, Sadashiv Karnick, Wei-Zhen Shen, and Jingli Zhang

 

The results in this study show that the rhodamine fluorophore can be specifically conjugated to Angiotensin II at Lys3 residue (substituted for a Val) without altering the biological activity of the parent compound. The conjugated peptide was characterized using HPLC, mass spectrometry, and N-terminal sequencing. The rhodamine-Angiotensin II binds effectively to AT1 receptor and gets internalized in clathrin coated vesicles by endocytosis. These results clearly suggest the usefulness of fluorophore-conjugated peptides in studies such as, ligand-receptor binding, and ligand-receptor complex internalization, for drug delivery using cell receptors and as an alternative to peptide hormone radioimmunoassays.

 

[Back to top] Virus-Cell Fusion Inhibitory Activity of Novel Analogue Peptides Based on the HP (2-20) Derived from N-Terminus of Helicobacter Pylori Ribosomal Protein L1

Eun-Rhan Woo, Dong Gun Lee, Young-Su Chang, Yoonkyung Park and Kyung-Soo Hahm

 

HP (2-20) (AKKVFKRLEKLFSKIQNDK) is the antibacterial sequence derived from N-terminus of Helicobacter pylori Ribosomal Protein L1 (RPL1). It has a broad-spectrum microbicidal activity in vitro that is thought to be related to the membrane-disruptive properties of the peptide. Based on the putative membrane-targeted mode of action, we postulated that HP (2-20) might be possessed virus-cell fusion inhibitory activity. To develop the novel virus-cell fusion inhibitory peptides, several analogues with amino acid substitution were designed to increase or decrease only net hydrophobic region. In particular, substitution of Gln and Asp for hydrophobic amino acid, Trp at position 17 and 19 of HP (2-20) (Anal 3) caused a dramatic increase in virus-cell fusion inhibitory activity without hemolytic effect.

 

[Back to top] Structure-Antibacterial Activity Relationship of Cecropin A Derivatives

Song Yub Shin, Keun Woo Lee, Yangmee Kim, Jae II Kim, Kyung-Soo Hahm and Shin-Won Kang

 

To investigate the effect of net positive charge, a-helicity and hydrophobicity of the peptides on antibacterial activity, we designed three kinds of cecropin A (CA) derivatives. Compared to CA, F3 with the highest net positive charge exhibited similar or slightly weaker antibacterial activity (MIC: 3.13~6.25 mM). F1 showed lower antibacterial activity than that of F3, even though it has higher hydrophobicity and a-helicity than F3. This result indicates that the net positive charge of cecropin A-like peptides appears to be a more important factor in antibacterial activity than a-helicity and hydrophobicity. The two peptides F1 and F2 possessed almost similar antibacterial activity, but F2 showed very lower activity in the membrane disruption than F1, suggesting other factors are involved in the antibacterial activity of the peptides as well as peptide-lipid interaction.

 

[Back to top] A Model for the Cytoplasmic Domain of the Influenza A Virus M2 Channel by Analogy to the HIV-1 Vpu Protein

José W. Saldanha, Peter E. Czabotar, Alan J. Hay and William R. Taylor

 

A model for the cytoplasmic domain of the M2 proton channel of influenza A virus was formulated based primarily on the cytoplasmic domain of the Vpu protein of HIV-1 using sequence similarity and structure prediction techniques. The model consists of a pair of antiparallel helices followed by a strand parallel to the first helix. Structural analogies with other proteins contribute support for features of the model and suggest ways in which the M2 cytoplasmic domain can interact with other viral and cellular factors.

 

[Back to top] Selective Precipitation of Haptoglobin and a2-Macroglobulin from Human Serum Using Alocasia macrorhiza Tuber Protein

B. Shivananda Nayak, N. Jagadish Ulloor and B. Shivaraj

 

Treatment of human serum with ammonium sulfate fraction (0-50%) of Alocasia macrorhiza tuber extract resulted in precipitation at neutral pH.  The precipitate was dissolved at pH 10.5 and chromatographed on Sephadex G-100 column. Two protein peaks were resolved. While the first peak represented a2-macroglobulin and haptoglobin, the second peak accounted for specific Alocasia protein. Incidentally the Alocasia protein was shown to be responsible for selective and specific precipitation of a2-macroglobulin and haptoglobin from serum.  Thus the plant protein in its pure form or in crude stage could be used for the rapid isolation of two of the prominent a2-globulins.

 

[Back to top] Biochemical Characterization of Apoptotic Cleavage of KH-Type Splicing Regulatory Protein (KSRP)/Far Upstream Element-Binding Protein 2 (FBP2)

Heeyoung Seok, Jinsun Cho, Minseok Cheon and II-Seon Park

 

Caspases, Asp-specific cysteine protease, cleave proteins upon apoptosis. To identify and characterize new caspase substrate in the nucleus, the proteome of the rat liver extracts was analyzed after the treatment with caspases. One of the identified proteins was KSRP/FBP2 that is preferentially cleaved by caspase-3 and –7 at two sites after Asp102 and Asp183. The second site was cleaved only in the protein produced in cells, but not in in vitro translated protein. These results indicate that more than the primary sequence may be important for the recognition by caspases.

 

[Back to top] Acyl-Gelatins for Cell-Hybrid Biomaterials: Preparation of Gelatins with High Melting Point and Affinity for Hydrophobic Surfaces

Keiichi Miyamoto, Hiroko Chinzei and Takashi Komai

 

In the development of cell-hybrid biomaterials, the functional activity of cells depends on the selective binding of cells to artificial ligands on the biomaterials. The extracellular matrix (ECM) is the most important ligand for cell activity. ECM is known to contain collagen, one of whose constituents is gelatin. Although natural gelatin has good cell attachment properties, the melting point of gelatin hydrogel is lower than body temperature. Thus, non-chemically cross-linked gelatin hydrogel is not a biomaterial that is used for prostheses. In the present study, we report the preparation of acyl-gelatin hydrogels with high melting point (>37˚C) and high affinity for hydrophobic surfaces for easy handling for transportation and adhesion activities on the hydrophobic surfaces. In addition, the doubling time of endothelial cells on the coated cell culture plate was faster than that of natural gelatin owing to the higher adhesion activity of acyl-gelatin. The results clearly demonstrated that the acyl-gelatin acted as an interface that enabled cell adhesion to artificial materials surfaces.

 

[Back to top] Synthesis of Alkyl and Aryl Esters of N-Protected b-Homoamino Acids from N-Protected a-Aminodiazoketones

G. R. Vasanthakumar, H. N. Gopi and V. V. Suresh Babu

 

A simple and concomitant esterification method for the synthesis of methyl, ethyl, t-butyl, benzyl, and 9-fluorenylmethyl esters of Fmoc-/Boc-/Z-b-homoamino acids employing Fmoc-/Boc-/Z-a-aminodiazoketones by Wolff rearrangement is described. The method offers good yield with purity.

 

[Back to top] Antibiotic Properties of Novel Synthetic Temporin A Analogs and a Cecropin A-Temporin A Hybrid Peptide

David Wade, Jan-Ingmar Flock, Charlotta Edlund, Ingegerd Löfving-Arvholm,Matti Sällberg, Tomas Bergman, Angela Silveira, Cecille Unson,Louise Rollins-Smith, Jerzy Silberring, Malcom Richardson, Pentti Kuusela and Hilkka Lankinen

 

A, 18 analogs, and a cecropin A-temporin A hybrid peptide were tested with antibiotic sensitive and resistant bacteria, fungi, human erythrocytes, and in clotting assays.Several peptides were active in these assays, and some analogs (D-TA, W1-TA, and Con-L4,G10) may be useful lead compounds for further antibiotics development.The activity of temporin A was found to be dependent upon several of its structural features, including amino acid composition and sequence, chirality, helicity, and positive charge.

 

[Back to top] A Direct Continuous pH-Spectrophotometric Assay for Arginine Kinase Activity

Yu Z., Pan J. and Zhou H.M.

 

A direct and continuous spectrophotometric method was developed for determining arginine kinase (phosphoarginine synthesis) activity. Protons are produced during the phosphoarginine synthesis course, so adding the complex acid-base indicator to this solution and monitoring the decrease of absorbance of the solution at 575 nm will follow the arginine kinase activity. For this condition, one activity unit of arginine kinase was defined as 1 mmol H+ produced in 1 minute in the enzymatic reaction catalyzed by arginine kinase.

 

[Back to top] Purification, Crystallization and Preliminary X-Ray Studies of Human Augmenter of Liver Regeneration

Chao-Neng Ji, Zai-Long Cai, Gen-Tao Cao, Gang Yin, Bing-Hua Jiao Tao Jiang, Guang Shu, Ji-Fang Mao, Yi Xie, and Yu-Min Mao

 

Human augmenter of liver regeneration has been expressed in Escherichia coli, purified and crystallized. The crystals belong to space group C222, with unit-cell parameters a=51.7 Å, b=78.8 Å, c=63.7 Å. Diffraction data were collected to 2.80 Å with a completeness of 99.9% (99.9% for the last shell), a Rsym value of 0.092(0.236) and an I/s(I) value of 6.2(2.7).