The primary structure of chicken muscle acylphosphatase isozyme Ch1

The amino acid sequence of chicken muscle acylphosphatase isozyme Ch1 was determined. The protein consists of 102 amino acid residues, does not contain histidine, and the NH2-terminus is acetylated: Ac-Ser-Ala-Leu-Thr-Lys-Ala-Ser-Gly-Ser- Leu-Lys-Ser-Val-Asp-Tyr-Glu-Val-Phe-Gly-Arg-Val-Gln-Gly-Val-Cys-Phe-Arg- Met- Tyr-Thr-Glu-Glu-Glu-Ala-Arg-Lys-Leu-Gly-Val-Val-Gly-Trp-Val-Lys-Asn- Thr- Ser-Gln-Gly-Thr-Val-Thr-Gly-Gln-Val-Gln-Gly-Pro-Glu-Asp-Lys-Val-Asn-Ala- Met- Lys-Ser-Trp-Leu-Ser-Lys-Val-Gly-Ser-Pro-Ser-Ser-Arg-Ile-Asp-Arg-Thr-Lys- Phe-Ser- Asn-Glu-Lys-Glu-Ile-Ser-Lys-Leu-Asp-Phe-Ser-Gly-Phe-Ser-Thr-Arg-Tyr-OH. This sequence differs in 44% of the total positions from the other isozyme (Ch2) of chicken muscle acylphosphatase (Ohba et al., the accompanying paper). The sequence of Ch1 has three substitutions from that of turkey muscle acylphosphatase; these are Ser from Ala at position 9, Ser from Arg at 47, and Lys from Asn at 83. The sequence has about 80% homology with those mammalian muscle acylphosphatases.     

The primary structure of chicken muscle acylphosphatase isozyme Ch2

The amino acid sequence of one, Ch2, of the two isozymes of chicken muscle acylphosphatase was determined. It consists of 98 amino acid residues with N-acetylalanine at the amino(N)-terminus and contains no cysteine: Ac-Ala-Gly-Ser-Glu- Gly-Leu-Met-Ser-Val-Asp-Tyr-Glu-Val-Ser-Gly-Arg-Val-Gln-Gly-Val-Phe-Phe- Arg- Lys-Tyr-Thr-Gln-Ser-Glu-Ala-Lys-Arg-Leu-Gly-Leu-Val-Gly-Trp-Val-Arg-Asn- Thr- Ser-His-Gly-Thr-Val-Gln-Gly-Gln-Ala-Gln-Gly-Pro-Ala-Ala-Arg-Val-Arg-Glu- Leu- Gln-Glu-Trp-Leu-Arg-Lys-Ile-Gly-Ser-Pro-Gln-Ser-Arg-Ile-Ser-Arg-Ala-Glu- Phe- Thr-Asn-Glu-Lys-Glu-Ile-Ala-Ala-Leu-Glu-His-Thr-Asp-Phe-Gln-Ile-Arg-Lys- COOH. The sequence differs in 44% of the total positions from the other isozyme, Ch1. Comparison of the sequence and the predicted conformational profile of Ch2 with those of Ch1 suggests that they share a common evolutionary origin and appear to have retained similar conformations throughout their evolutionary development.     

Purification and properties of porcine testis acylphosphatase

Acylphosphatase has been purified from porcine testis and its properties were compared with those of porcine skeletal muscle acylphosphatase. The molecular weight of the testis enzyme was found to be 10,600, similar to that of porcine skeletal muscle acylphosphatase, on sedimentation equilibrium analysis. The specific activity of the testis enzyme was 10,800 mumol/min/mg at 25 degrees C with benzoyl phosphate as substrate, i.e., higher than that of the muscle enzyme, 7,200 mumol/min/mg, under the same conditions. The pI of the testis enzyme was 8.3, i.e., lower than that of the muscle enzyme, 10.6. There were marked differences in the amino acid compositions of the two enzymes. In particular two histidine residues were present in the testis enzyme but none were present in the muscle enzyme, and no cysteine residue was present in the testis enzyme but one was present in the muscle enzyme. The carboxyl terminal amino acid of the testis enzyme seemed to be lysine, while that of the muscle enzyme is tyrosine. The peptide maps of the testis and muscle enzymes indicated considerable differences in the amino acid sequences of the two enzymes. Differences in the antigenic structures of the two enzymes were demonstrated on enzyme linked immunoassaying and double immunodiffusion. These results indicate that the porcine testis acylphosphatase is an isozyme different from the porcine skeletal muscle acylphosphatase.     

Ontogenic expression of the two isozymes, Ch1 and Ch2, of chicken muscle acylphosphatase

Activities of the two isozymes, Ch1 and Ch2, of chicken muscle acylphosphatase were measured in breast muscles, leg muscles, and livers of developing chicks from day 11 in ovo to day 15 of free life. Measurement was performed using rabbit antibodies which could selectively precipitate Ch1 or Ch2. The activity contents of both Ch1 and Ch2 in muscles were low before hatching but rapidly increased after hatching. Ch1 showed a more marked increase than Ch2. In liver, on the other hand, the activity contents of Ch1 and Ch2 remained low throughout the period of pre- and post-hatching.     

Distribution and classification of acylphosphatase isozymes

Distributions of acylphosphatase isozymes among organs of several animal species were investigated. Organ extracts of pig and chicken were treated with isozyme-specific antibodies, subjected to electrophoresis on a polyacrylamide gel, then the gel was stained for acylphosphatase activity. Both animals showed three activity bands; one band was named common type isozyme because of its wide distribution in testis, muscle, brain, heart, spleen, kidney, liver, and erythrocyte, and the other two bands were named muscle type isozymes because of their localization in skeletal muscle. This classification was supported by selective and quantitative reactions of the isozymes to the isozyme-specific antibodies. Because the two bands of the muscle type have the same amino acid sequence and differ only in modifications on an -SH group, it is suggested that pig and chicken have only the two major types of acylphosphatase. This conclusion was supported by similar experiments on dog, human, rabbit, and pigeon.     

Amino acid sequence of acylphosphatase from porcine skeletal muscle

The amino acid sequence of acylphosphatase from porcine skeletal muscle was determined. It consists of 98 amino acid residues with N-acetylserine at the amino (N)-terminus: Ac-Ser-Thr-Ala-Arg-Pro-Leu-Lys-Ser-Val-Asp-Tyr-Glu-Val-Phe-Gly -Arg-Val-Gln-Gly-Val-Cys-Phe-Arg-Met-Tyr-Thr-Glu-Asp-Glu-Ala-Arg-Lys-Ile -Gly-Val-Val-Gly-Trp-Val-Lys-Asn-Thr-Ser-Lys-Gly-Thr-Val-Thr-Gly-Gln -Val-Gln-Gly-Pro-Glu-Glu-Lys-Val-Asn-Ser-Met-Lys-Ser-Trp-Leu-Ser-Lys -Ile-Gly-Ser-Pro-Ser-Ser-Arg-Ile-Asp-Arg-Thr-Asn-Phe-Ser-Asn-Glu-Lys- Thr-Ile-Ser-Lys-Leu-Glu-Tyr-Ser-Asn-Phe-Ser-Ile-Arg-Tyr-OH. This sequence has three substitutions of amino acid residues, i.e., Thr/Ala, Ile/Val, and Ile/Val at positions 26, 68, and 96, respectively, from that of horse muscle acylphosphatase, formerly the only mammalian acylphosphatase with known sequence.     

The complete amino acid sequence of bovine skeletal muscle acylphosphatase

The primary structure of bovine skeletal muscle acylphosphatase was determined by performing the sequence analyses of the complete series of tryptic peptides. The amino acid composition of the entire series of peptic peptides was used to reconstruct the sequence by the overlapping method. The proposed structure is further confirmed by analogy with known amino acid sequences of acylphosphatase from skeletal muscle of other vertebrate species. The length of the polypeptide chain is 98 residues, identical to the length of the enzymes from other known mammalian species, but different from that found in turkey. The enzyme is NH2-acetylated and a comparison with the analogous molecular forms from other vertebrate species indicates that there are several long polypeptide stretches strictly conserved (93-97% identical position among mammals, and about 80% between calf and turkey enzymes).     

Duck skeletal muscle acylphosphatase: Primary structure

The complete amino acid sequence of duck skeletal muscle acylphosphatase is presented. The sequence was studied by the manual Edman degradation of the complete series of tryptic peptides and the amino acid composition of peptic peptides. The NH₂-terminus is acetylated, and the polypeptide consists of 102 amino acid residues. The sequence is compared with other known acylphosphatases from the skeletal muscle of several vertebrate species.     

Amino acid sequence of phosvitin derived from the nucleotide sequence of part of the chicken vitellogenin gene

The amino acid sequence of the egg yolk storage protein phosvitin has been deduced from the nucleotide sequence of part of the chicken vitellogenin gene. Of the phosvitin sequence, 210 amino acids including the N-terminal residue are contained on one large exon, whereas the remaining six amino acids are encoded on the next exon. Phosvitin contains a core region of 99 amino acids, consisting of 80 serines, grouped in runs of maximally 14 residues interspersed by arginines, lysines, and asparagines. The serines of the core region are encoded by AGC and AGT codons exclusively and the arginines by AGA and AGG, which results in a continuous stretch of 99 codons with adenine in the first position. The N-terminal quarter of the phosvitin sequence contains 16 serines grouped in a cluster with alanines and threonines and coded mainly by TCX triplets. The C-terminal part includes 27 serines, preferentially coded by AGC and AGT, 13 histidine residues, and the sequence ...Asn-Gly-Ser... at which the carbohydrate moiety of phosvitin is attached. Heteroduplex formation between cloned DNAs from chicken and Xenopus vitellogenin genes shows that the phosvitin sequence contains a stretch of highly conserved sequence.     

Rabbit skeletal muscle acylphosphatase: the amino acid sequence of form Ra1

Acylphosphatase was purified from rabbit skeletal muscle by a procedure involving an affinity chromatography step on immunoadsorbent and subsequent ion-exchange chromatography. Three molecular forms with acylphosphatase activity, named Ra1, Ra2, and Ra3, were purified and characterized with respect to molecular weight, amino acid composition, and main kinetic parameters. The amino acid sequence of Ra1 is given in the present paper. The Ra1 form consists of a single polypeptide chain of 98 amino acid residues and contains only one cysteine residue at position 21 that is S-S bound to glutathione. The polypeptide chain has an acetyl group blocking the NH2 terminus. Ra1, Ra2, and Ra3 are compared with the corresponding molecular forms isolated from skeletal muscle of horse and turkey.     

The complete amino acid sequence of actins from bovine aorta, bovine heart, bovine fast skeletal muscle, and rabbit slow skeletal muscle. A protein-chemical analysis of muscle actin differentiation.

Complete amino acid sequences for four mammalian muscle actins are reported: bovine skeletal muscle actin, bovine cardiac actin, the major component of bovine aorta actin, and rabbit slow skeletal muscle actin. The number of different actins in a higher mammal for which full amino acid sequences are now available is therefore increased from two to five. Screening of different smooth muscle tissues revealed in addition to the aorta type actin a second smooth muscle actin, which appears very similar if not identical to chicken gizzard actin. Since the sequence of chicken gizzard actin is known, six different actins are presently characterized in a higher mammal. The two smooth muscle actins--bovine aorta actin and chicken gizzard actin--differ by only three amino acid substitutions, all located in the amino-terminal end. In the rest of their sequences both smooth muscle actins share the same four amino acid substitutions, which distinguish them from skeletal muscle actin. Cardiac muscle actin differs from skeletal muscle actin by only four amino acid exchanges. No amino acid substitutions were found when actins from rabbit fast and slow skeletal muscle were compared. In addition we summarize the amino acid substitution patterns of the six different mammalian actins and discuss their tissue specificity. The results show a very close relationship between the four muscle actins in comparison to the nonmuscle actins. The amino substitution patterns indicate that skeletal muscle actin is the highest differentiated actin form, whereas smooth muscle actins show a noticeably cloer relation to nonmuscle actins. By these criteria cardiac muscle actin lies between skeletal muscle actin and smooth muscle actins.     

The Complete Amino Acid Sequence of Actins from Bovine Aorta, Bovine Heart, Bovine Fast Skeletal Muscle, and Rabbit, Slow Skeletal Muscle

Complete amino acid sequences for four mammalian muscle actins are reported: bovine skeletal muscle actin, bovine cardiac actin, the major component of bovine aorta actin, and rabbit slow skeletal muscle actin. The number of different actins in a higher mammal for which full amino acid sequences are now available is therefore increased from two to five. Screening of different smooth muscle tissues revealed in addition to the aorta type actin a second smooth muscle actin, which appears very similar if not identical to chicken gizzard actin. Since the sequence of chicken gizzard actin is known, six different actins are presently characterized in a higher mammal.
The two smooth muscle actins—bovine aorta actin and chicken gizzard actin—differ by only three amino acid substitutions, all located in the amino-terminal end. In the rest of their sequences both smooth muscle actins share the same four amino acid substitutions, which distinguish them from skeletal muscle actin. Cardiac muscle actin differs from skeletal muscle actin by only four amino acid exchanges. No amino acid substitutions were found when actins from rabbit fast and slow skeletal muscle were compared.
In addition we summarize the amino acid substitution patterns of the six different mammalian actins and discuss their tissue specificity. The results show a very close relationship between the four muscle actins in comparison to the nonmuscle actins. The amino substitution patterns indicate that skeletal muscle actin is the highest differentiated actin form, whereas smooth muscle actins show a noticeably closer relation to nonmuscle actins. By these criteria cardiac muscle actin lies between skeletal muscle actin and smooth muscle actins.     

Sequence of cDNAs encoding actin depolymerizing factor and cofilin of embryonic chicken skeletal muscle: two functionally distinct actin-regulatory proteins exhibit high structural homology.

Two actin-regulatory proteins of 19 and 20 kDa are involved in the regulation of actin assembly in developing chicken skeletal muscle. They are homologous with actin depolymerizing factor (ADF) and cofilin, a pH-dependent actin-modulating protein, which were originally discovered in chicken and mammalian brain, respectively. In this study, full-length cDNA clones were isolated by screening a lambda gt11 cDNA library constructed from poly(A+) RNA of embryonic chicken skeletal muscle with the antibodies specific for each protein, and their complete sequences were determined. The chicken cofilin cDNA encoded a protein of 166 amino acids, the sequence of which had over 80% identity with that of porcine brain cofilin. The amino acid sequence of the ADF was 165 amino acids and showed about 70% identity with either chicken or mammalian cofilin, in spite of the fact that ADF and cofilin are functionally distinct. Like chicken and mammalian cofilin, ADF contained a sequence similar to the nuclear transport signal sequence of SV40 large T antigen. ADF and cofilin shared a hexapeptide identical with the amino-terminal sequence of tropomyosin as well as the regions homologous to other actin-regulatory proteins, including depactin, gelsolin, and profilin. The overall nucleotide sequences and Southern blot analysis of genomic DNA, however, indicated that the two proteins were derived from different genes.     

Molecular cloning and nucleotide sequences of the complementary DNAs to chicken skeletal muscle myosin two alkali light chain mRNAs.

We report here the molecular cloning and sequence analysis of DNAs complementary to mRNAs for myosin alkali light chain of chicken embryo and adult leg skeletal muscle. pSMA2-1 contained an 818 base-pair insert that includes the entire coding region and 5' and 3' untranslated regions of A2 mRNA. pSMA1-1 contained a 848 base-pair insert that included the 3' untranslated region and almost all of the coding region except for the N-terminal 13 amino acid residues of the A1 light chain. The 741 nucleotide sequences of A1 and A2 mRNAs corresponding to C-terminal 141 amino acid residues and 3' untranslated regions were identical. The 5' terminal nucleotide sequences corresponding to N-terminal 35 amino acid residues of A1 chain were quite different from the sequences corresponding to N-terminal 8 amino acid residues and of the 5' untranslated region of A2 mRNA. These findings are discussed in relation to the structures of the genes for A1 and A2 mRNA.     

A 7.5-kb 3'-Terminal cDNA Sequence of Chicken Skeletal Muscle Nebulin Reveals Its Actin Binding Regions

Nebulin is an approximately 700 kDa filamentous protein in vertebrate skeletal muscle. It binds to the Z line and also binds side-by-side to the entire thin (actin) filament in a sarcomere. Nebulin is currently thought to be a molecular ruler regulating the length of the thin filament to 1 mum. The complete sequence of human skeletal muscle nebulin was determined by . Because of its large size, only fragmental sequence information has been available for nebulins other than human skeletal muscle. This paper describes for the first time the sequence of about one third (C terminal region) of chicken skeletal muscle nebulin. It was found that the fundamental structure of human nebulin, consisting of 35 amino acid repeats (modules) plus C terminal serine-rich and SH3 domains linked to the Z line are well conserved with chicken nebulin. Sequence identity ranged from 74 to 91%. There were super-repeats (seven modules), a first linker repeat, simple repeat and a second linker repeat in addition to the Z line binding region as in human nebulin. However, there were 2 fewer modules in the first linker repeat and 6 fewer in the simple repeat in chicken nebulin as compared to human nebulin. Two isoforms of chicken nebulin were sequenced indicating insertion of approximately 6 or 11 modules to a structure similar to that of human nebulin. Recombinant first linker repeats M51 approximately 56 were shown to bind to actin using the ELISA technique as well as human nebulin recombinants.     

Amino acid sequence of acylphosphatase from rabbit skeletal muscle

The complete amino acid sequence of acylphosphatase from rabbit skeletal muscle has been elucidated by automatic Edman degradation of peptides obtained from staphylococcal protease and trypsin digestions. The enzyme consisted of a single polypeptide chain of 98 amino acid residues, lacking only histidine. Its amino (N)-terminus was blocked by an acetyl group. The presented sequence of rabbit muscle enzyme was compared with those of equine and porcine muscle enzymes. There were four unique replacements, i.e., Arg-4, Asp-28, Arg-31, and Glu-56 in the sequences of both equine and porcine muscle enzymes were replaced by Gly, Gly, Lys, and Asp, respectively, in that of rabbit muscle enzyme. Extensive structural homology was observed among the three enzymes.     

Entropic stabilization of proteins and its proteomic consequences

Evolutionary traces of thermophilic adaptation are manifest, on the whole-genome level, in compositional biases toward certain types of amino acids. However, it is sometimes difficult to discern their causes without a clear understanding of underlying physical mechanisms of thermal stabilization of proteins. For example, it is well-known that hyperthermophiles feature a greater proportion of charged residues, but, surprisingly, the excess of positively charged residues is almost entirely due to lysines but not arginines in the majority of hyperthermophilic genomes. All-atom simulations show that lysines have a much greater number of accessible rotamers than arginines of similar degree of burial in folded states of proteins. This finding suggests that lysines would preferentially entropically stabilize the native state. Indeed, we show in computational experiments that arginine-to-lysine amino acid substitutions result in noticeable stabilization of proteins. We then hypothesize that if evolution uses this physical mechanism as a complement to electrostatic stabilization in its strategies of thermophilic adaptation, then hyperthermostable organisms would have much greater content of lysines in their proteomes than comparably sized and similarly charged arginines. Consistent with that, high-throughput comparative analysis of complete proteomes shows extremely strong bias toward arginine-to-lysine replacement in hyperthermophilic organisms and overall much greater content of lysines than arginines in hyperthermophiles. This finding cannot be explained by genomic GC compositional biases or by the universal trend of amino acid gain and loss in protein evolution. We discovered here a novel entropic mechanism of protein thermostability due to residual dynamics of rotamer isomerization in native state and demonstrated its immediate proteomic implications. Our study provides an example of how analysis of a fundamental physical mechanism of thermostability helps to resolve a puzzle in comparative genomics as to why amino acid compositions of hyperthermophilic proteomes are significantly biased toward lysines but not similarly charged arginines.     

Calsequestrin, an intracellular calcium-binding protein of skeletal muscle sarcoplasmic reticulum, is homologous to aspartactin, a putative laminin-binding protein of the extracellular matrix

Calsequestrin was isolated from chicken fast-twitch skeletal muscle, and partial amino terminal sequence was determined. The sequence (NH2) EEGLNFPTYDGKDRVIDLNE shows high identity with known mammalian calsequestrins contained in the Protein Identification Resource data bank (1). Most importantly, this 20 amino acid sequence shares complete identity with the amino terminus of aspartactin, a putative laminin-binding protein of the extracellular matrix (2, 3). The possible relationship of aspartactin to calsequestrin is discussed.     

Polymorphisms of Chicken TLR3 and 7 in Different Breeds

Toll-like receptors (TLRs) mediate immune responses via the recognition of pathogen-associated molecular patterns (PAMPs), thus playing important roles in host defense. Among the chicken (Ch) TLR family, ChTLR3 and 7 have been shown to recognize viral RNA. In our earlier studies, we have reported polymorphisms of TLR1, 2, 4, 5, 15 and 21. In the present study, we amplified TLR3 and 7 genes from different chicken breeds and analyzed their sequences. We identified 7 amino acid polymorphism sites in ChTLR3 with 6 outer part sites and 1 inner part site, and 4 amino acid polymorphism sites in ChTLR7 with 3 outer part sites and 1 inner part site. These results demonstrate that ChTLR genes are polymorphic among different chicken breeds, suggesting a varied resistance across numerous chicken breeds. This information might help improve chicken health by breeding and vaccination.