Functional relationship of serine 90 phosphorylation and the surrounding putative salt bridge in bovine prolactin

Schenck, Emanuel; Canfield, Jeffrey M.; Brooks, Charles L.

doi:10.1016/s0303-7207(03)00123-0

Cited by 12 publications

(19 citation statements)

References 30 publications

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“…These results agree well with our own findings here and show that, with the appropriate neighboring residues, phosphorylation in α-helices can be highly stabilizing. In contrast, Brooks and coworkers ( 41 ) showed how phosphorylation of a serine residue in bovine prolactin could destabilize a modeled α-helix and result in reduced activity. Their supposition was that phosphorylation of Ser90 would place a phosphate group in a steric clash with an already stabilizing, highly conserved, salt bridge between the neighboring Arg89 and Asp93 residues.…”

Section: Resultsmentioning

confidence: 95%

Anticooperativity in a Glu−Lys−Glu Salt Bridge Triplet in an Isolated α-Helical Peptide

Iqbalsyah

Doig

2005

Biochemistry

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Phosphorylation is ubiquitous in control of protein activity, yet its effects on protein structure are poorly understood. Here we investigate the effect of serine phosphorylation in the interior of an α-helix when a salt bridge is present between the phosphate group and a positively charged side chain (in this case lysine) at i,i + 4 spacing. The stabilization of the helix is considerable and can overcome the intrinsically low preference of phosphoserine for the interior of the helix. The effect is pH dependent, as both the lysine and phosphate groups are titratable, and so calculations are given for several charge combinations. These results, with our previous work, highlight the different, context-dependent effects of phosphorylation in the α-helix. The interaction between the phosphate 2− group and the lysine side chain is the strongest yet recorded in helix-coil studies. The results are of interest both in de novo design of peptides and in understanding the structural modes of control by phosphorylation.Phosphorylation and dephosphorylation have long been known as control mechanisms for various processes in biochemistry, and roughly one-third of all proteins in eukaryotes are estimated to undergo reversible phosphorylation (1). Since the middle of the last century it has been known that protein activity can be controlled by the addition or removal of a phosphate group (2-5). The control of gene expression, macromolecule production, and cellular proliferation have since been shown to be orchestrated through multiple intracellular signal transduction pathways. These pathways, or protein kinase cascades, propagate signals received at the plasma membrane to the interior of the cell through a series of phosphorylation-controlled events.The mechanisms of action of phosphorylation are, however, still relatively poorly understood at the structural level, though many studies of individual systems now show some conformational differences between proteins and synthetic peptides before and after phosphorylation (see, e.g., refs 6-13). Previous work from our own group (14) and others (15-17) has shown that phosphorylation at the N-terminus stabilizes α-helices but also that the effect is position dependent. When interior serine residues are phosphorylated, the effect is greatly destabilizing, but at the three N-terminal positions it is greatly stabilizing (phosphoserine at the N2 position in a helix is the most stabilizing interaction yet found at this position). More recent work has suggested that protein phosphorylation sites, especially those for serine and threonine, are predominantly disordered prior to phosphorylation and that phosphorylation sites resemble natively unstructured proteins in terms of their charge, hydrophobicity, and amino acid composition. Some of the exceptions to these sites may be crystallization artifacts, and in others it may be that the substrate undergoes an order- † This work was funded by The Wellcome Trust (award reference 065106). Europe PMC Funders Author ManuscriptsEurope PMC ...

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Section: Resultsmentioning

confidence: 95%

Anticooperativity in a Glu−Lys−Glu Salt Bridge Triplet in an Isolated α-Helical Peptide

Iqbalsyah

Doig

2005

Biochemistry

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“…One possibility is pH‐dependent destabilization of the secondary hydrophobic bundle at the upper ends of the long loops indirectly alters the structure or stability of the short helix at the other end of the loops, known to play a critical role in receptor recognition. In fact, we feel that such a mechanism appears likely for the lowering of receptor‐binding affinity for bovine PRL phosphorylated at S90,21, 22 given its buried position within this secondary hydrophobic core and its intimate relationship with H59 (assuming the bovine and human PRL tertiary structures are sufficiently similar). Alternatively, local destabilization and the associated increased mobility of the long loops in hPRL may increase susceptibility to enzymatic proteolysis, either as part of the mechanism for generation of the potently antiangiogenic 16 kDa N‐terminal fragment of hPRL23, 24 or during lysosomal degradation of the hormone after endocytosis 25…”

Section: Resultsmentioning

confidence: 97%

Contribution of individual histidines to the global stability of human prolactin

et al. 2009

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A member of the family of hematopoietic cytokines human prolactin (hPRL) is a 23k kDa polypeptide hormone, which displays pH dependence in its structural and functional properties. The binding affinity of hPRL for the extracellular domain of its receptor decreases 500-fold over the relatively narrow, physiologic pH range from 8 to 6; whereas, the affinity of human growth hormone (hGH), its closest evolutionary cousin, does not. Similarly, the structural stability of hPRL decreases from 7.6 to 5.6 kcal/mol from pH 8 to 6, respectively, whereas the stability of hGH is slightly increased over this same pH range. hPRL contains nine histidines, compared with hGH's three, and they are likely responsible for hPRL's pH-dependent behavior. We have systematically mutated each of hPRL's histidines to alanine and measured the effect on pH-dependent global stability. Surprisingly, a vast majority of these mutations stabilize the native protein, by as much as 2-3 kcal/mol. Changes in the overall pH dependence to hPRL global stability can be rationalized according to the predominant structural interactions of individual histidines in the hPRL tertiary structure. Using double mutant cycles, we detect large interaction free energies within a cluster of nearby histidines, which are both stabilizing and destabilizing to the native state. Finally, by comparing the structural locations of hPRL's nine histidines with their homologous residues in hGH, we speculate on the evolutionary role of replacing structurally stabilizing residues with histidine to introduce pH dependence to cytokine function.

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“…1). The Pro 96 and Gly 131 of mature cmPRL1 were residues found to be well conserved among all GH/PRL family members; these residues are considered to be important in the binding of molecules to their receptors (Goffin et al, 1996;Schenck et al, 2003).…”

Section: -1 Cloningmentioning

confidence: 99%

“…First, the C-terminal region, in particular the residues between Cys 173 and Cys 190 (positions in mature cmPRL1) is well conserved among all examined GH/PRL family molecules. In cmPRL1, Pro 96 and Gly 131 , the residues which significantly contribute to the receptor binding ability of the molecules (Goffin et al, 1996;Schenck et al, 2003), were conserved between known PRL1s. Although the C-termini of cmPRL1 and known PRL1 proteins terminate with the conserved Cys residue, the cmGH has the extension of two amino acid residues after Cys 182 in its C-terminal end; such an extension of C-terminal residues is a feature of known GHs and SLs.…”

Section: -2 Evolution Of Gh/prl Familymentioning

confidence: 99%

Discovery of conventional prolactin from the holocephalan elephant fish, Callorhinchus milii

Yamaguchi

Takagi

Kuraku³

et al. 2015

General and Comparative Endocrinology

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The conventional prolactin (PRL), also known as PRL1, is an adenohypophysial hormone that critically regulates various physiological events in reproduction, metabolism, growth, osmoregulation, among others. PRL1 shares its evolutionary origin with PRL2, growth hormone (GH), somatolactin and placental lactogen, which together form the GH/PRL hormone family. Previously, several bioassays implied the existence of PRL1 in elasmobranch pituitaries. However, to date, all attempts to isolate PRL1 from chondrichthyans have been unsuccessful. Here, we cloned PRL1 from the pituitary of the holocephalan elephant fish, Callorhinchus milii, as the first report of chondrichthyan PRL1. The putative mature protein of elephant fish PRL1 (cmPRL1) consists of 198 amino acids, containing two conserved disulfide bonds. The orthologous relationship of cmPRL1 to known vertebrate PRL1s was confirmed by the analyses of molecular phylogeny and gene synteny. The cmPRL1 gene was similar to teleost PRL1 genes in gene synteny, but was distinct from amniote PRL1 genes, which most likely arose in an early amphibian by duplication of the ancestral PRL1 gene. The mRNA of cmPRL1 was predominantly expressed in the pituitary, but was considerably less abundant than has been previously reported for bony fish and tetrapod PRL1s; the copy number of cmPRL1 mRNA in the pituitary was less than 1% and 0.1% of that of GH and pro-opiomelanocortin mRNAs, respectively. The cells expressing cmPRL1 mRNA were sparsely distributed in the rostral pars distalis. Our findings provide a new insight into the studies on molecular and functional evolution of PRL1 in vertebrates.

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Functional relationship of serine 90 phosphorylation and the surrounding putative salt bridge in bovine prolactin

Cited by 12 publications

References 30 publications

Anticooperativity in a Glu−Lys−Glu Salt Bridge Triplet in an Isolated α-Helical Peptide

Anticooperativity in a Glu−Lys−Glu Salt Bridge Triplet in an Isolated α-Helical Peptide

Contribution of individual histidines to the global stability of human prolactin

Discovery of conventional prolactin from the holocephalan elephant fish, Callorhinchus milii

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