Characterization of γ-crystallin from a catfish: Structural characterization of one major isoform with high methionine by cDNA sequencing

F. M. Pan, W. C. Chang, C. H. Lin, A. L. Hsu, S. H. Chiou

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

γ-Crystallin is the major and most abundant lens protein present in the eye lens of most teleostean fishes. To facilitate structural characterization of γ-crystallins isolated from the lens of the catfishes (Clarias fuscus), a cDNA mixture was synthesized from the poly(A)+mRNA isolated from fresh eye lenses, and amplification by polymerase chain reaction (PCR) was adopted to obtain cDNAs encoding various γ-crystallins. Plasmids of transformed E. coli strain JM109 containing amplified γ-crystallin cDNAs were purified and prepared for nucleotide sequencing by the dideoxynucleotide chain-termination method. Sequencing more than five clones containing DNA inserts of 0.52 kb revealed the presence of one major isoform with a complete reading frame of 534 base pairs, covering a γ-crystallin (γM1) with a deduced protein sequence of 177 amino acids excluding the initiating methionine. It was of interest to find that this crystallin of pI 9.1 contains a high-methionine content of 15.3% in contrast to those γ-crystallins of low-methionine content from most mammalian lenses. Sequence comparisons of catfish γM1-crystallin with those published sequences of γ-crystallins from carp, bovine and mouse lenses indicate that there is approx. an 82% sequence homology between the catfish and the carp species of piscine class whereas only 51-58% homology is found between mammals and the catfish. Moreover the differences in the hydropathy profiles for these two groups of γ-crystallins, i.e. one with a high-methionine content from teleostean fishes and the other with a low-methionine content from mammalian species, reflect a distinct variance in the polarity distributions of surface amino acids in these crystallins. The extensive molecular characterization of various γ-crystallins from different species of the evolutionarily lower vertebrates such as the catfish may provide some insight into the mechanism underlying the evolution of the multigene γ-crystallin family.

Original languageEnglish
Pages (from-to)725-732
Number of pages8
JournalBiochemistry and Molecular Biology International
Volume35
Issue number4
Publication statusPublished - Dec 1 1995
Externally publishedYes

Fingerprint

Catfishes
Crystallins
Methionine
Protein Isoforms
Complementary DNA
Lenses
Crystalline Lens
Carps
Fish
Fishes
Dideoxynucleotides
Amino Acids
Reading Frames
Mammals
Polymerase chain reaction
Multigene Family
Sequence Homology
Base Pairing
Escherichia coli
Amplification

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Genetics

Cite this

Characterization of γ-crystallin from a catfish : Structural characterization of one major isoform with high methionine by cDNA sequencing. / Pan, F. M.; Chang, W. C.; Lin, C. H.; Hsu, A. L.; Chiou, S. H.

In: Biochemistry and Molecular Biology International, Vol. 35, No. 4, 01.12.1995, p. 725-732.

Research output: Contribution to journalArticle

@article{6222df05e43a464bb61e576ee972a75a,
title = "Characterization of γ-crystallin from a catfish: Structural characterization of one major isoform with high methionine by cDNA sequencing",
abstract = "γ-Crystallin is the major and most abundant lens protein present in the eye lens of most teleostean fishes. To facilitate structural characterization of γ-crystallins isolated from the lens of the catfishes (Clarias fuscus), a cDNA mixture was synthesized from the poly(A)+mRNA isolated from fresh eye lenses, and amplification by polymerase chain reaction (PCR) was adopted to obtain cDNAs encoding various γ-crystallins. Plasmids of transformed E. coli strain JM109 containing amplified γ-crystallin cDNAs were purified and prepared for nucleotide sequencing by the dideoxynucleotide chain-termination method. Sequencing more than five clones containing DNA inserts of 0.52 kb revealed the presence of one major isoform with a complete reading frame of 534 base pairs, covering a γ-crystallin (γM1) with a deduced protein sequence of 177 amino acids excluding the initiating methionine. It was of interest to find that this crystallin of pI 9.1 contains a high-methionine content of 15.3{\%} in contrast to those γ-crystallins of low-methionine content from most mammalian lenses. Sequence comparisons of catfish γM1-crystallin with those published sequences of γ-crystallins from carp, bovine and mouse lenses indicate that there is approx. an 82{\%} sequence homology between the catfish and the carp species of piscine class whereas only 51-58{\%} homology is found between mammals and the catfish. Moreover the differences in the hydropathy profiles for these two groups of γ-crystallins, i.e. one with a high-methionine content from teleostean fishes and the other with a low-methionine content from mammalian species, reflect a distinct variance in the polarity distributions of surface amino acids in these crystallins. The extensive molecular characterization of various γ-crystallins from different species of the evolutionarily lower vertebrates such as the catfish may provide some insight into the mechanism underlying the evolution of the multigene γ-crystallin family.",
author = "Pan, {F. M.} and Chang, {W. C.} and Lin, {C. H.} and Hsu, {A. L.} and Chiou, {S. H.}",
year = "1995",
month = "12",
day = "1",
language = "English",
volume = "35",
pages = "725--732",
journal = "IUBMB Life",
issn = "1521-6543",
publisher = "Wiley-Blackwell",
number = "4",

}

TY - JOUR

T1 - Characterization of γ-crystallin from a catfish

T2 - Structural characterization of one major isoform with high methionine by cDNA sequencing

AU - Pan, F. M.

AU - Chang, W. C.

AU - Lin, C. H.

AU - Hsu, A. L.

AU - Chiou, S. H.

PY - 1995/12/1

Y1 - 1995/12/1

N2 - γ-Crystallin is the major and most abundant lens protein present in the eye lens of most teleostean fishes. To facilitate structural characterization of γ-crystallins isolated from the lens of the catfishes (Clarias fuscus), a cDNA mixture was synthesized from the poly(A)+mRNA isolated from fresh eye lenses, and amplification by polymerase chain reaction (PCR) was adopted to obtain cDNAs encoding various γ-crystallins. Plasmids of transformed E. coli strain JM109 containing amplified γ-crystallin cDNAs were purified and prepared for nucleotide sequencing by the dideoxynucleotide chain-termination method. Sequencing more than five clones containing DNA inserts of 0.52 kb revealed the presence of one major isoform with a complete reading frame of 534 base pairs, covering a γ-crystallin (γM1) with a deduced protein sequence of 177 amino acids excluding the initiating methionine. It was of interest to find that this crystallin of pI 9.1 contains a high-methionine content of 15.3% in contrast to those γ-crystallins of low-methionine content from most mammalian lenses. Sequence comparisons of catfish γM1-crystallin with those published sequences of γ-crystallins from carp, bovine and mouse lenses indicate that there is approx. an 82% sequence homology between the catfish and the carp species of piscine class whereas only 51-58% homology is found between mammals and the catfish. Moreover the differences in the hydropathy profiles for these two groups of γ-crystallins, i.e. one with a high-methionine content from teleostean fishes and the other with a low-methionine content from mammalian species, reflect a distinct variance in the polarity distributions of surface amino acids in these crystallins. The extensive molecular characterization of various γ-crystallins from different species of the evolutionarily lower vertebrates such as the catfish may provide some insight into the mechanism underlying the evolution of the multigene γ-crystallin family.

AB - γ-Crystallin is the major and most abundant lens protein present in the eye lens of most teleostean fishes. To facilitate structural characterization of γ-crystallins isolated from the lens of the catfishes (Clarias fuscus), a cDNA mixture was synthesized from the poly(A)+mRNA isolated from fresh eye lenses, and amplification by polymerase chain reaction (PCR) was adopted to obtain cDNAs encoding various γ-crystallins. Plasmids of transformed E. coli strain JM109 containing amplified γ-crystallin cDNAs were purified and prepared for nucleotide sequencing by the dideoxynucleotide chain-termination method. Sequencing more than five clones containing DNA inserts of 0.52 kb revealed the presence of one major isoform with a complete reading frame of 534 base pairs, covering a γ-crystallin (γM1) with a deduced protein sequence of 177 amino acids excluding the initiating methionine. It was of interest to find that this crystallin of pI 9.1 contains a high-methionine content of 15.3% in contrast to those γ-crystallins of low-methionine content from most mammalian lenses. Sequence comparisons of catfish γM1-crystallin with those published sequences of γ-crystallins from carp, bovine and mouse lenses indicate that there is approx. an 82% sequence homology between the catfish and the carp species of piscine class whereas only 51-58% homology is found between mammals and the catfish. Moreover the differences in the hydropathy profiles for these two groups of γ-crystallins, i.e. one with a high-methionine content from teleostean fishes and the other with a low-methionine content from mammalian species, reflect a distinct variance in the polarity distributions of surface amino acids in these crystallins. The extensive molecular characterization of various γ-crystallins from different species of the evolutionarily lower vertebrates such as the catfish may provide some insight into the mechanism underlying the evolution of the multigene γ-crystallin family.

UR - http://www.scopus.com/inward/record.url?scp=0029550633&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0029550633&partnerID=8YFLogxK

M3 - Article

C2 - 7627123

AN - SCOPUS:0029550633

VL - 35

SP - 725

EP - 732

JO - IUBMB Life

JF - IUBMB Life

SN - 1521-6543

IS - 4

ER -