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UniProtKB/Swiss-Prot variant pages

UniProtKB/Swiss-Prot P55157: Variant p.Tyr528His

Microsomal triglyceride transfer protein large subunit
Gene: MTTP
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Variant information Variant position: help 528 The position of the amino-acid change on the UniProtKB canonical protein sequence.
Type of variant: help LP/P [Disclaimer] The variants are classified into three categories: LP/P, LB/B and US.
  • LP/P: likely pathogenic or pathogenic.
  • LB/B: likely benign or benign.
  • US: uncertain significance
Residue change: help From Tyrosine (Y) to Histidine (H) at position 528 (Y528H, p.Tyr528His). Indicates the amino acid change of the variant. The one-letter and three-letter codes for amino acids used in UniProtKB/Swiss-Prot are those adopted by the commission on Biochemical Nomenclature of the IUPAC-IUB.
Physico-chemical properties: help Change from large size and aromatic (Y) to medium size and polar (H) The physico-chemical property of the reference and variant residues and the change implicated.
BLOSUM score: help 2 The score within a Blosum matrix for the corresponding wild-type to variant amino acid change. The log-odds score measures the logarithm for the ratio of the likelihood of two amino acids appearing by chance. The Blosum62 substitution matrix is used. This substitution matrix contains scores for all possible exchanges of one amino acid with another:
  • Lowest score: -4 (low probability of substitution).
  • Highest score: 11 (high probability of substitution).
More information can be found on the following page
Variant description: help In ABL; does not reduce interaction with P4HB/PDI and APOB; inhibits triglyceride transfer activity. Any additional useful information about the variant.
Other resources: help Links to websites of interest for the variant.


Sequence information Variant position: help 528 The position of the amino-acid change on the UniProtKB canonical protein sequence.
Protein sequence length: help 894 The length of the canonical sequence.
Location on the sequence: help LQRYDLPFITDEVKKTLNRI Y HQNRKVHEKTVRTAAAAIIL The residue change on the sequence. Unless the variant is located at the beginning or at the end of the protein sequence, both residues upstream (20) and downstream (20) of the variant will be shown.
Residue conservation: help The multiple alignment of the region surrounding the variant against various orthologous sequences. 
Human                         LQRYDLPFITDEVKKTLNRIYHQNRKVHEKTVRT-AAAAIIL

Mouse                         LQRYDVSFITDEVKKTLNRIYHQNRKVHEKTVRT-TAAAVI

Rat                           LQRYDASFITDEVKKTLNRIYHQNRKVHEKTVRT-TAAAVI

Pig                           LQRYDAPFITDEVKKTMNRIYHQTRKVHEKTVRT-TAAAVI

Zebrafish                     LQRYDPALITAEVKKALNRIYHQNQRIYEKNVRA-AAADVI

Caenorhabditis elegans        ILAASKNLYETQLTHKLIKLFRNTCSQETPTSHSQLAIDIL

Drosophila                    LKAFPLGSFNSSHRLQFESIFYQRKRRFDSSART-LALDII
Sequence annotation in neighborhood: help The regions or sites of interest surrounding the variant. In general the features listed are posttranslational modifications, binding sites, enzyme active sites, local secondary structure or other characteristics reported in the cited references. The "Sequence annotation in neighborhood" lines have a fixed format:
  • Type: the type of sequence feature.
  • Positions: endpoints of the sequence feature.
  • Description: contains additional information about the feature.
TypePositionsDescription
Chain 19 – 894 Microsomal triglyceride transfer protein large subunit
Domain 28 – 659 Vitellogenin
Alternative sequence 152 – 894 Missing. In isoform 2.
Mutagenesis 528 – 528 Y -> F. Does not inhibit triglyceride transfer activity.
Mutagenesis 528 – 528 Y -> K. Inhibits triglyceride transfer activity.
Mutagenesis 540 – 540 R -> A. Strongly reduces triglyceride transfer activity.
Mutagenesis 540 – 540 R -> K. Does not inhibit triglyceride transfer activity and apolipoprotein B secretion.
Helix 518 – 528



Literature citations
Novel missense MTTP gene mutations causing abetalipoproteinemia.
Miller S.A.; Burnett J.R.; Leonis M.A.; McKnight C.J.; van Bockxmeer F.M.; Hooper A.J.;
Biochim. Biophys. Acta 1842:1548-1554(2014)
Cited for: VARIANTS ABL ARG-264; HIS-528; CYS-540 AND SER-649; CHARACTERIZATION OF VARIANTS ABL ARG-264; HIS-528; CYS-540; HIS-540 AND SER-649; FUNCTION; INTERACTION WITH APOB AND P4HB; MUTAGENESIS OF TYR-528;
Disclaimer: Any medical or genetic information present in this entry is provided for research, educational and informational purposes only. They are not in any way intended to be used as a substitute for professional medical advice, diagnostic, treatment or care.